Steel pipe pile connection structure, steel pipe pile foundation, and steel pipe pile connection method

Abstract

To stably connect a piping arranged along an inner surface of a steel pipe pile and improve workability and economy of a processing process, in a connecting portion that connects steel pipe piles in an axial direction using an inner fitting member and an outer fitting member.SOLUTION: A steel pipe pile connection structure comprises: an inner fitting member joined to an axial end of a first pile body; an outer fitting member joined to an axial end of a second pile body; a first pipe joined to an inner peripheral surface of the first pile body; and a second pipe joined to an inner peripheral surface of the second pile body. The inner fitting member includes a first fitting portion fitted into an inside of the outer fitting member and a through groove portion forming an opening on an outer peripheral surface of the inner fitting member and making an inside of the inner fitting member communicate with an outside of the first fitting portion. The outer fitting member includes a second fitting portion that is fitted onto an outside of the inner fitting member. The first pipe and the second pipe are connected through the through groove portion and a passage formed between the first fitting portion and the second fitting portion.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a connection structure for steel pipe piles, a steel pipe pile foundation, and a method for connecting steel pipe piles. [Background technology]

[0002] The construction method for steel pipe piles is selected depending on the condition of the ground, but one method improves construction efficiency by combining rotary press-in and high-pressure water injection from the tip. On the other hand, when the pile length is long, multiple piles are connected axially and driven into the pile. 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 is to connect the water pipes by placing them near the center of the cross section of the pile body. However, 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.

[0003] 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. In 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, thereby 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 of ensuring sufficient bending rigidity.

[0004] When connecting steel pipe piles in which high-pressure water piping is arranged along the inner circumferential 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 form a stepped part that protrudes inside the pile body at the connection part, making it difficult to stably connect the piping at the connection part. Therefore, in hard ground or ground with a lot of closed soil, for example, the above-mentioned fitting connection method has not been applied due to the possibility that the piping connection part may become detached. Therefore, Patent Document 5 describes a technology for stably connecting piping arranged along the inner circumferential surface of a steel pipe pile by forming a through hole that communicates the inside and outside of the inner fitting member and connecting the piping through it. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-200910 [Patent Document 2] Japanese Patent Application Publication No. 09-264018 [Patent Document 3] Japanese Patent Application Laid-Open No. 2016-29250 [Patent Document 4] Japanese Patent Application Laid-Open No. 2015-143466 [Patent Document 5] Japanese Patent Publication No. 2023-150113 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the case of the technology described in Patent Document 5, the work of connecting the piping to the fitting requires inserting a jig into a narrow through-hole, leaving room for improvement in terms of workability. Also, the cost of drilling the through-hole that connects the inside and outside of the fitting member is high, leaving room for improvement in terms of the economy of the processing process.

[0007] Therefore, the present invention 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 part that connects steel pipe piles in the axial direction using an inner fitting member and an outer fitting member, and that can improve workability and the economy of the processing process. [Means for solving the problem]

[0008] [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 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, wherein the inner fitting member includes a first fitting portion that fits into the inside of the outer fitting member and a through groove portion that forms an opening on the outer peripheral surface of the inner fitting member and 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, and the first pipe and the second pipe are connected through a passage formed between the through groove portion and the first fitting portion and the second fitting portion. [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 groove portion and the passage. [3] A connection structure for steel pipe piles according to [1], wherein an extension of the first pipe or the second pipe passes through the through groove and the passage. [4] A connection structure for a steel pipe pile described in any one of [1] to [3], in which a notch is formed on the outer surface of the outer fitting member in a circumferential position aligned with the passage, and the notch forms the opening together with the through groove portion. [5] A steel pipe pile connection structure according to any one of [1] to [4], further comprising a cover body attached to the opening. [6] A connection structure for steel pipe piles described in any one of [1] to [5], wherein the passage is formed by a groove portion formed in at least one of the first fitting portion and the second fitting portion. [7] A connection structure for a steel pipe pile described in any one of [1] to [6], 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 and sandwiching a gap portion in the circumferential direction of the inner fitting member, 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 and sandwiching a gap portion in the circumferential direction of the outer fitting member, and the first protrusions and the second protrusions are configured to engage with each other when the inner fitting member is rotated to a predetermined position while fitted inside the outer fitting member. [8] A connection structure for a steel pipe pile described in [7], 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 of the inner fitting member and the outer fitting member are aligned. [9] A connecting structure for a steel pipe pile described in [7], wherein a first protrusion notch is formed in the circumferential middle portion or end portion of at least one of the inner fitting members of the first protrusion, and a second protrusion notch is formed in the circumferential middle portion or end portion of at least one of the outer fitting members of the second protrusion, 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 of the inner fitting member and the outer fitting member are aligned, thereby forming the passage.

[10] A steel pipe pile foundation including at least one steel pipe pile connection structure described in any one of [1] to [9].

[11] 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 in an inner fitting member joined to the axial end of the first pile body into the inside of a second fitting portion formed in 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 in the outer peripheral surface of the inner fitting member, where a through groove portion that communicates the inside of the inner fitting member with the outside of the first fitting portion is formed in the outer peripheral surface of the inner fitting member, and the first pipe and the second pipe are connected through the through groove portion and a passage formed between the first fitting portion and the second fitting portion.

[12] A method of connecting steel pipe piles as described in

[11] , in which a notch is formed on the outer surface of the outer fitting member in a circumferential position aligned with the passage, and the notch forms the opening together with the through groove portion.

[13] A method for connecting steel pipe piles as described in

[11] or

[12] , further comprising the step of attaching a cover to the opening after connecting the first pipe and the second pipe.

[14] A method for connecting steel pipe piles described in any one of

[11] to

[13] , 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.

[15] A method for connecting steel pipe piles described in any one of

[11] to

[14] , wherein a connecting pipe is used to connect the first pipe and the second pipe, and 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.

[16] A method for connecting steel pipe piles according to any one of

[11] to

[15] , 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 and sandwiching a gap portion in the circumferential direction of the inner fitting member; 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 and sandwiching a gap portion in the circumferential direction of the outer fitting member; and the step of fitting the first fitting portion into the inside of the second fitting portion includes a step of engaging the first protrusion and the second protrusion with each other by rotating the inner fitting member to a predetermined position while it is fitted into the inside of the outer fitting member.

[17] The method for connecting steel pipe piles described in

[16] , wherein 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.

[18] The method for connecting steel pipe piles described in

[16] , 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. [Effects of the Invention]

[0009] According to the above configuration, the first and second pipes arranged along the inner circumferential surface of the pile body can be stably connected in the steel pipe pile connection structure. Furthermore, according to the above configuration, since a through groove is formed instead of a through hole, it is easy to insert a jig into the opening formed by the through groove, improving workability. Furthermore, since the through groove can be formed, for example, by a cutting process, processing costs are reduced and the economy of the processing process is improved. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a perspective view showing a state before connection of a connection structure for steel pipe piles according to a first embodiment of the present invention. [Figure 2] 2 is a cross-sectional view showing the state after the connection structure shown in FIG. 1 is connected. [Figure 3] 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. FIG. [Figure 4] 10 is a graph showing the analysis results of a load test on a steel pipe pile connection structure. [Figure 5] 10A and 10B are diagrams illustrating an example of a connector that connects a pipe and a connecting pipe. [Figure 6] 10A and 10B are diagrams illustrating an example of a connector that connects a pipe and a connecting pipe. [Figure 7] 10A and 10B are diagrams illustrating an example of a connector for connecting connecting pipes to each other. [Figure 8] FIG. 1 is a schematic view showing a first example of a method for connecting steel pipe piles according to a first embodiment of the present invention. [Figure 9] FIG. 3 is a schematic view showing a second example of the method for connecting steel pipe piles according to the first embodiment of the present invention. [Figure 10] 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. [Figure 11] 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. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In this specification and drawings, components having substantially the same functional configurations are designated by the same reference numerals, and redundant description will be omitted.

[0012] FIG. 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. 2 is a cross-sectional view showing the state after connection of the connection structure shown in FIG. 1, and FIG. 3 is a partial cross-sectional view showing a state in which the connection of pipes has been completed in the connection structure shown in FIGS. 1 and 2. A 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, pipes 51 and 52, a connecting pipe 6, and a cover 7 (see FIG. 3 for the connecting pipe 6 and the cover 7). The pile bodies 21 and 22 are each formed of a steel pipe and function as a single steel pipe pile when connected via the inner fitting member 3 and the outer fitting member 4. The steel pipe pile is driven into the ground using, for example, a rotary press-in method or a vibrohammer method, but the construction method is not particularly limited.

[0013] In the following description, the axial direction refers to the axial direction of the steel pipe pile formed by connecting the pile main bodies 21, 22 via the inner fitting member 3 and the 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. Since the pile main bodies 21, 22, the inner fitting member 3, and the outer fitting member 4 are arranged so as to be coaxial after connection, the axial, circumferential, and radial directions are common to these members.

[0014] 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 welded portions 23 and 24, respectively. The inner fitting member 3 is fitted inside the outer fitting member 4, rotated axially to a predetermined position, and fixed with a rotation prevention key (not shown), thereby connecting the pile main bodies 21 and 22 joined to the inner fitting member 3 and the outer fitting member 4, respectively. The inner fitting member 3 includes a joint portion 31 joined to the pile main body 21, and a fitting portion 32 (first fitting portion) formed subsequent to the joint portion 31 and fitted 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 protruding portions 322 (first protruding portions) protruding outward from the reduced diameter portion 321 and formed with gaps in between in the circumferential direction. The length (dimension in the circumferential direction) of the protrusions 322 is smaller than the gaps between the protrusions 322 in the circumferential direction.

[0015] On the other hand, the outer fitting member 4 includes a joint portion 41 joined to the pile main body 22 and a fitting portion 42 (second fitting portion) formed next to the joint portion 41 and fitted to 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 a plurality of protruding portions 422 (second protruding portions) protruding inward from the expanded diameter portion 421 and 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, 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.

[0016] The pipes 51 and 52 are fluid pipes extending in the axial direction of the pile bodies 21 and 22. The pipe 51 (first pipe) is joined to the inner circumferential surface of the pile body 21, and the pipe 52 (second pipe) is joined to the inner circumferential surface of the pile body 22. When the pipes 51 and 52 are steel pipes, the pipes 51 and 52 may be welded to the inner circumferential surfaces of the pile bodies 21 and 22. Alternatively, the pipes 51 and 52 may be fixed by a retainer (not shown) welded to the inner circumferential surfaces of the pile bodies 21 and 22. As will be described later, in this embodiment, the pipes 51 and 52 are connected via a connecting pipe 6. By supplying high-pressure water from the ground to the tip of the steel pipe pile being driven via the pipes 51 and 52 and the connecting pipe 6, the steel pipe pile can be smoothly penetrated into the ground (water jet method).

[0017] As shown in FIG. 2 , in this embodiment, an opening is formed in the outer peripheral surface of the inner fitting member 3, more specifically, the joint portion 31, and a through groove portion 33 is formed to connect the inside of the inner fitting member 3 to the outside of the fitting portion 32. Furthermore, a groove portion 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 groove portion 33. Specifically, the groove portion 324 extends from the outlet of the through groove portion 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 portion 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 portion 424 of the outer fitting member 4 is formed so as to be aligned with the groove portion 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 on the pile main body 22 side to the end opposite the pile main 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 are opposed to each other, forming a passage through which the connecting pipe 6 connecting the piping 51 and 52 passes.

[0018] In the above example, for example, when the gap between the inclined surfaces 323, 423 is large when the inner fitting member 3 is rotated axially while fitted inside the outer fitting member 4, and the dimension by which the groove widens the passage may be small, or when either of the fitting portions 32, 42 has a thickness sufficient to form a deep groove, the groove 324 or the groove 424 may be formed on one of the inclined surfaces 323, 423, and no groove may be formed on the other. Also, when the gap between the inclined surfaces 323, 423 when the inner fitting member 3 is rotated axially while fitted inside the outer fitting member 4 is equal to or larger than the outer diameter of the connecting pipe 6, it is not necessary to form a groove on either of the inclined surfaces 323, 423. That is, in this embodiment, the passage through which the connecting pipe 6 passes is formed in a portion where the positions of the gaps of the protruding portion 322 and the gaps of the protruding portion 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., a portion where the positions of the inclined surfaces 323, 423 are aligned, and as necessary, the groove portion 324 or the groove portion 424 is formed in at least one of the inclined surfaces 323, 423. Note that the "aligned portion" does not necessarily mean that the positions of the inclined surfaces 323, 423 in the circumferential direction are completely aligned, but it is sufficient that the positions of the inclined surfaces 323, 423 at least partially overlap in the circumferential direction.

[0019] Furthermore, in this embodiment, a notch 44 is formed in the outer peripheral surface of the outer fitting member 4 in a circumferential position aligned with the passage formed by the through groove 33 and the grooves 324, 424. The opening formed by the through groove 33 on the inner fitting member 3 side and the notch 44 on the outer fitting member 4 side allows the step of inserting the connecting pipe 6 into the through groove 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. If an opening large enough for such construction can be formed only by the through groove 33, the notch 44 in the outer fitting member 4 may not be formed. For example, the notch 44 may have a width approximately the same as that of the through groove 33 and be wider than the width (circumferential dimension) of the grooves 324, 424, as in the illustrated example, but is not limited to such an example.

[0020] 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-groove portion 33 and grooves 324 and 424. Connecting pipe 6 is connected to pipe 51 by connector 71 and to pipe 52 by 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 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, a portion of connecting pipe 6 may be made of a flexible pipe, and the other portion may be made of a rigid tubular member.

[0021] 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.

[0022] After the process of connecting the pipes 51 and 52 through the opening formed by the through groove 33 and the notch 44 is completed, the cover 7 is attached to the notch 44 to seal the opening. A groove may be formed on the inner surface of the cover 7 to ensure 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 receiving resistance from the ground. This protection provided by the cover 7 allows the connecting pipe 6 to be formed from a soft and inexpensive material that can withstand water pressure. Note that 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. Therefore, the cover 7 is preferably attached by a method other than welding, such as bolting, in which bolts are inserted from the outside of the cover 7 into threaded holes formed in the inner fitting member 3 and the outer fitting member 4.

[0023] Note that, for example, in cases where there is no possibility that the connecting pipe 6 will protrude outside the steel pipe pile even when water pressure is applied, or in cases where the connecting pipe 6 is made of a material with sufficient strength and does not require protection, the connecting pipe 6 may be exposed without the cover 7 being attached. Alternatively, to protect the connecting pipe 6 without using the cover 7, the opening formed by the through groove portion 33 and the notch 44 may be filled with a solidifying material.

[0024] FIG. 4 is a graph showing the analysis results of a load test of a steel pipe pile connection structure. The vertical displacements of a connection structure (Example) having a through-groove according to an embodiment of the present invention and a connection structure (Comparative Example) having a through-hole as described in JP 2023-150113 A were calculated by analysis. The steel pipes in both the Example and Comparative Example had a diameter of 1000 mm and a pipe thickness of 16 mm. As a result, there was almost no difference in vertical displacement relative to the applied load between the Example having a through-groove and the Comparative Example having a through-hole. In the high-load range exceeding 4000 kN, the Comparative Example yielded earlier than the Example. From these results, it can be seen that the connection structure having a through-groove according to an embodiment of the present invention exhibits structural strength equivalent to or greater than that of a connection structure having a through-hole as described in JP 2023-150113 A.

[0025] 5 and 6 are diagrams showing examples of connectors for connecting a pipe and a connecting pipe. In the example shown in FIG. 5, 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. 6, 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 example of connector 71A described above can also be applied to connector 72, and the example of connector 72B can also be applied to connector 71.

[0026] Fig. 7 is a diagram showing an example of a connector for connecting connecting pipes. In the example shown in Fig. 7, connector 73A is composed of inner pipe 731 joined to connecting pipe 61, sheath pipe 732 joined to connecting pipe 62, and 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 Figs. 5 to 7, and various structures such as couplers known as connecting structures for fluid pipes can be used.

[0027] FIG. 8 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. In this embodiment, as shown in FIG. 8(a), 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 groove 33 of the inner fitting member 3, the groove 324 (not shown) formed in the inclined surface 323, the groove 424 (not shown) formed in the inclined surface 423 of the outer fitting member 4, and the notch 44 formed in the outer fitting member 4 are aligned. Therefore, as shown in FIG. 8(b), a connecting pipe 62 can be inserted through the opening formed by the through groove 33 and the notch 44, and then, as shown in FIG. 8(c), the connecting pipe 62 can be inserted through the grooves 324 and 424 to connect to the piping 52. Although not shown, a connecting pipe 61 is then inserted through the opening of the through groove 33 and the notch 44 in a similar manner and inserted into the inner fitting member 3 through the through groove 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 opening of the through groove portion 33 and the notch 44, the piping 51 and 52 can be connected via the connecting pipe 6. Furthermore, after that, a step of attaching the lid body 7 to the opening of the through groove portion 33 and the notch 44 may be performed.

[0028] FIG. 9 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. 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 through groove 33 or the notch 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 protruding portions 322, 422 even when the inner fitting member 3 is rotated relative to the outer fitting member 4. After the inner fitting member 3 is rotated 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 extending from the pipe 51 via the through groove 33 to be connected near the opening formed by the through groove 33 and the notch 44. Similarly, the connection pipe 61 stored in advance inside the pipe 51 may be pulled out. Also, 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.

[0029] 10 is a schematic diagram showing an example of a connection structure and connection method for a steel pipe pile according to a second embodiment of the present invention. In the second embodiment, a passage through which the connecting pipe 6 passes is formed by a notch 325A (first protruding portion notch) formed in the circumferential middle portion of the protruding portion 322 of the inner fitting member 3 and a notch 425A (second protruding portion notch) formed in the circumferential middle portion 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 passage formed by aligning the positions of the notches 325A and 425A can be connected by inserting the connecting pipe 6 through the opening formed by the through groove portion 33 and the notches 44, as shown in (b) and (c), through the through groove portion 33 and the notches 325A and 425A, and connecting the piping 51 and 52.

[0030] FIG. 11 is a schematic diagram showing an example of a connecting structure and a connecting 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 protruding portions 322A, 422A among the multiple protruding portions 322, 422 arranged in the circumferential direction of the inner fitting member 3 and the outer fitting member 4 is made shorter than the other protruding portions 322, 422 due to notches (first and second protruding portion notches) formed at the circumferential ends. The space created by these notches serves as a passageway for the connecting pipe 6. If the connecting pipe 62 on the outer fitting member 4 is positioned along the notched portion of the protruding portion 422A as shown in (a), the connecting pipe 62 does not interfere with the protruding portions 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, are aligned to form a passage, and the position of this passage is aligned with the position of the through groove portion 33. Here, by connecting the connecting pipe 61 and the connecting pipe 62, which are separately connected to the pipe 51, the pipes 51 and 52 can be connected via the connecting pipe 6.

[0031] According to the embodiment of the present invention as described above, the pipes 51 and 52 are connected through the through groove 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 and 52 may be connected by the connecting pipe 6, or by extensions of either or both of the pipes 51 and 52. No additional members are required to secure the connecting pipe 6 or the extensions of the pipes 51 and 52. Furthermore, the pipes 51 and 52 or the connecting pipe 6 can be connected from the outside after the pile bodies 21 and 22 are connected through openings formed by the through groove 33 and the notches 44 provided on the outer surfaces of the inner fitting member 3 and the outer fitting member 4, allowing for highly safe and stable construction. In the section where the inner fitting member 3 and the outer fitting member 4 of the connecting structure 1 are fitted together, the extension of the connecting pipe 6 or the piping 51, 52 does not pass inside the step where the inner fitting member 3 or the outer fitting member 4 protrudes inward, so it is less likely to encounter resistance from, for example, soil and sand (blocking soil) flowing into the interior from the tip of the steel pipe pile. Therefore, even in hard ground or ground with a lot of blocking soil, the connection part of the piping is less likely to come loose, and even in such cases, the connecting structure 1 can be applied to omit on-site welding and construct a steel pipe pile foundation with improved workability.

[0032] For example, in the method of connecting steel pipe piles as described above with reference to Figures 8 to 11, the presence of an opening with a through groove formed on the outer surface of the inner fitting member makes it easier to insert the jig into the inner fitting member when handling connecting pipes or wires using the jig, improving workability.

[0033] Although the above describes an example in which the fitting portions 32, 42 of the inner fitting member 3 and the outer fitting member 4 included in the connecting structure 1 are formed with the reduced-diameter portion 321, the expanded-diameter portion 421, and the protrusions 322, 422, the configurations of the inner fitting member and the outer fitting member are not limited to these examples. 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, a through-groove is formed in the inner fitting member, and a passage is formed by, for example, a groove formed on at least one of the outer circumferential surface of the fitting portion of the inner fitting member and the inner circumferential surface of the fitting portion of the outer fitting member, and by aligning these grooves in the circumferential direction, pipes can be connected to each other in the same manner as in the above-described embodiment. [Explanation of symbols]

[0034] 1...connecting structure, 21, 22...pile 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 groove portion, 4...outer fitting member, 41...joint portion, 42...fitting portion, 421...expanded diameter portion, 422, 422A...protruding portion, 423...inclined surface surface, 424...groove portion, 425A...notch, 44...notch, 51, 52...piping, 6, 61, 62...connecting pipe, 7...lid body, 71, 71A, 72, 72B, 73, 73A...connector, 74...wire, 711...threaded joint, 712...bushing, 721...outer pipe, 722...inner pipe, 723...O-ring, 731...inner pipe, 732...pipe, 733...water-stop rubber.

Claims

1. 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 groove portion that forms an opening on an outer peripheral surface of the inner fitting member and 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, A steel pipe pile connection structure in which the first pipe and the second pipe are connected through the through groove portion and a passage formed between the first fitting portion and the second fitting portion.

2. The steel pipe pile connection structure according to claim 1 , further comprising a connecting pipe connected to the first pipe and the second pipe and passing through the through groove portion and the passage.

3. The steel pipe pile connection structure according to claim 1 , wherein an extension of the first pipe or the second pipe passes through the through groove and the passage.

4. A notch is formed on the outer peripheral surface of the outer fitting member in a circumferential position aligned with the passage, The steel pipe pile connection structure according to claim 1 , wherein the notch forms the opening together with the through groove.

5. The steel pipe pile connection structure according to claim 1 , further comprising a lid attached to the opening.

6. The steel pipe pile connection structure according to claim 1 , wherein the passage is formed by a groove portion formed in at least one of the first fitting portion and the second fitting portion.

7. 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 sandwiched between them in the circumferential direction of the inner fitting member, The second fitting portion includes an expanded diameter portion whose inner diameter gradually increases toward the end portion opposite the second pile body in the axial direction, and a plurality of second protrusions formed inside the expanded diameter portion with gaps sandwiched between them in the circumferential direction of the outer fitting member, The steel pipe pile connection structure according to claim 1, 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.

8. A steel pipe pile connection structure as described in claim 7, wherein when the inner fitting member is rotated to the predetermined position while fitted inside the outer fitting member, the passage is formed in a portion where the gap portion of the first protrusion and the gap portion of the second protrusion in the circumferential direction of the inner fitting member and the outer fitting member are aligned.

9. a first protrusion notch is formed in an intermediate portion or an end portion of at least one of the first protrusions in the circumferential direction of the inner fitting member; a second protrusion notch is formed in an intermediate portion or an end portion of at least one of the second protrusions in the circumferential direction of the outer fitting member; A connecting structure for steel pipe piles as described in claim 7, 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 of the inner fitting member and the outer fitting member are aligned, thereby forming the passage.

10. A steel pipe pile foundation comprising at least one steel pipe pile connection structure according to any one of claims 1 to 9.

11. 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; a step of connecting a first pipe joined to the inner peripheral surface of the first pile main body and a second pipe joined to the inner peripheral surface of the second pile main body through an opening formed in the outer peripheral surface of the inner fitting member by a through groove portion that communicates the inside of the inner fitting member with the outside of the first fitting portion; A method for connecting steel pipe piles, wherein the first pipe and the second pipe are connected through the through groove portion and a passage formed between the first fitting portion and the second fitting portion.

12. A notch is formed on the outer peripheral surface of the outer fitting member in a circumferential position aligned with the passage, The method for connecting steel pipe piles according to claim 11 , wherein the notch forms the opening together with the through groove.

13. The method for connecting steel pipe piles according to claim 11 or 12, further comprising the step of attaching a lid to the opening after connecting the first pipe and the second pipe.

14. 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, 13. The method for connecting steel pipe piles according to claim 11 or claim 12, 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.

15. a connecting pipe is used to connect the first pipe and the second pipe; 13. A method for connecting steel pipe piles according to claim 11 or claim 12, wherein the step of connecting the first pipe and the second pipe includes the 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.

16. 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 sandwiched between them in the circumferential direction of the inner fitting member, The second fitting portion includes an expanded diameter portion whose inner diameter gradually increases toward the end portion opposite the second pile body in the axial direction, and a plurality of second protrusions formed inside the expanded diameter portion with gaps sandwiched between them in the circumferential direction of the outer fitting member, 13. A method for connecting steel pipe piles as described in claim 11 or claim 12, 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 protruding portion and the second protruding portion with each other.

17. 17. The method for connecting steel pipe piles according to claim 16, wherein the step of connecting the first pipe and the second pipe includes the 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.

18. 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 the inner fitting member is fitted inside the outer fitting member, 17. The method for connecting steel pipe piles according to claim 16, 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.

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