JP2012046945A - Joint structure of rotary press-in steel pipe pile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a joint structure of a rotary press-in steel pipe pile, which dispenses with field welding while enabling bidirectional rotation transfer, which can be mechanically connected by simple operations, and which hardly requires work on the steel pipe pile itself by virtue of a simple constitution.SOLUTION: A joint pipe 3 for being fitted into inner peripheries of steel pipe piles is provided throughout a lower portion of an upside steel pipe pile 1A and an upper portion of a downside steel pipe pile 1B, which are connected to each other. A part in a circumferential direction of the joint pipe 3 is provided with a groove-shaped portion 5 which is formed by plastically deforming a pipe wall in a groove shape. Engaging protrusions 6 and 6, which make an axial entry into the groove-shaped portion 5 of the joint pipe 3 to be engaged in a circumferential direction, are provided on the inner peripheral surfaces of the upper and lower steel pipe piles 1A and 1B, respectively. The joint pipe 3 is provided with a steel pipe pile receiving flange 4 which transfers a downward axial load to a section between the upper and lower steel pipe piles 1A and 1B.

Description

  The present invention relates to a joint structure of a rotary press-fit type steel pipe pile that is a pile foundation or the like that supports a structure such as a building or a house, and a construction method thereof.

  Some steel pipe piles, such as pile foundations, are provided with a spiral tip blade at the lower end for easy press-fitting work to the ground, or by press-fitting while rotating without providing a tip blade. When steel pipe piles can be pressed into the ground deeply, the length of one steel pipe pile is insufficient, so a plurality of pipes are sequentially connected while being pressed into the ground. When connecting steel pipe piles, it is necessary to enable rotation transmission in the rotary press-fit type steel pipe piles. Moreover, in order to change due to an error in the press-fitting position of the steel pipe pile or to correct the inclination, it may be necessary to rotate the steel pipe pile in the reverse direction and pull it out. Therefore, it is necessary to enable transmission of reverse rotation.

  For this reason, in the rotary press-fit type steel pipe pile, the upper and lower steel pipe piles are joined by welding or the like, but on-site welding is troublesome and requires a welding engineer who is a special technician. Various joint structures have been proposed in which such problems due to field welding are eliminated, and the connection is mechanically simple and strong so that rotation can be transmitted without relying on welding (for example, Patent Document 1).

JP 2001-200355 A

  Conventional connection by field welding takes time and effort as described above, and requires a welding engineer who is a special engineer. In addition, the mechanical joint structure proposed in Patent Document 1 does not require on-site welding, but welds an annular joint material to upper and lower steel pipe piles that are connected to each other, and connects the upper and lower joint materials to each other. It shall be mechanically connected. Therefore, it is necessary to make a steel pipe pile into a steel pipe pile with an annular joint material, and the steel pipe pile to be prepared becomes a special structure and the joint structure becomes complicated. In addition, the upper and lower joint materials have a cross-sectional shape with a lack of phase, and the joint material itself is complicated in shape and takes time and labor, resulting in high costs.

  The object of the present invention is to provide rotary press-fitting that allows bidirectional rotation transmission but does not require on-site welding, can be mechanically connected by simple operations, has a simple structure, and requires only a small amount of processing of the steel pipe pile itself. It is to provide a joint structure for type steel pipe piles.

The joint structure of the rotary press-fit type steel pipe pile according to the present invention is a connection type rotary press-fit type steel pipe pile that is joined with a steel pipe pile made up of circular steel pipes one after the other and rotated against the ground. A joint structure that connects to each other,
A joint pipe that fits to the inner circumference of the lower steel pipe pile and the upper part of the lower steel pipe pile connected to each other is provided, and the pipe wall is grooved in a part of the circumferential direction of the joint pipe. A groove portion that is recessed toward the inner diameter side that has been plastically deformed is provided, and an engagement protrusion that engages in the circumferential direction by entering the groove portion of the joint pipe in the axial direction on the inner peripheral surface of the upper and lower steel pipe piles. And a drop-preventing projection for preventing the joint pipe from falling by engaging with the lower steel pipe pile. The drop prevention protrusion may be a steel pipe pile receiving member provided on an intermediate outer periphery in the length direction of the joint pipe and interposed between a lower end surface of the upper steel pipe pile and an upper end surface of the lower steel pipe pile. It may be a local protrusion that engages with the engaging protrusion of the lower steel pipe pile. Of the steel pipe piles that are successively connected up and down, the steel pipe pile at the lower end may have a spiral tip blade.

  According to this configuration, after press fitting the lower steel pipe pile into the ground, the lower part of the joint pipe is fitted to the upper end of the lower steel pipe pile, and the lower end of the upper steel pipe pile is fitted to the upper part of the joint pipe. This fitting is performed by relative axial movement of the steel pipe pile and the joint pipe. At the time of this fitting, the engaging protrusions of the upper and lower steel pipe piles are inserted into the groove portion of the joint pipe. . The joint pipe is prevented from falling by engaging the drop preventing protrusion with the lower steel pipe pile. In this connected state, a pressure input is given while rotating the upper steel pipe pile by a pile driving machine. At this time, the downward compression force due to the pressure input acting on the steel pipe pile or the load of the upper structure is directly transmitted between the end faces of the upper and lower steel pipe piles, and the steel pipe pile receiving force is transmitted to the joint pipe. Is provided via the steel pipe pile receiver. The rotation applied to the upper steel pipe pile is caused by the engagement between the engaging protrusion of the upper steel pipe pile and the groove-shaped part, and the engagement between the groove-shaped part and the engaging protrusion of the lower steel pipe pile. It is transmitted via the engaging protrusion and the groove portion. Since the engagement is between the groove-shaped portion and the engaging protrusion that enters the groove-shaped portion, rotation transmission in both forward and reverse directions is possible. Since it is possible to transmit rotation in both forward and reverse directions, the steel pipe pile can be lifted by the reverse rotation of the tip blade at the lower end of the pile and pulled out by rotating it with a pile driving machine. In addition, when not providing a front-end | tip blade | blade, it is preferable to give simple drop-off prevention of the grade which can support the drawing-out force of a pile between a joint pipe and an up-and-down steel pipe pile. This drop-off prevention can be performed, for example, by inserting bolts or pins over holes provided in alignment with the steel pipe pile and the joint pipe.

  Thus, bidirectional transmission of rotation is possible, but it is only necessary to fit the joint pipe and the steel pipe pile, and to insert / remove the engagement protrusion of the steel pipe pile with respect to the groove portion of the joint pipe. No welding is required, and mechanical connection can be achieved with simple operations. Moreover, it is only necessary to provide an engagement protrusion on the steel pipe pile, and for example, the processing of the steel pipe pile itself is small as compared with the case of welding an annular joint material over the entire circumference of the end of the steel pipe pile. The joint pipe needs to be processed into a groove section and an axial load transmission section such as a steel pipe pile receiver, but the groove section may be plastically processed into a part of a short steel pipe used as a material for the joint pipe. Therefore, unlike what is processed into a long steel pipe pile, it can be processed easily. In addition, the steel pipe pile receiving rod is provided by welding of a ring member or the like, but since it can be performed by factory welding, processing such as highly reliable welding can be performed.

In this invention, it is good that the pipe wall part which comprises the said groove-shaped part of the said joint pipe is a thickening processed part which became thicker than the other pipe wall part in this joint pipe.
The groove portion of the joint pipe engages with the engagement protrusion of the steel pipe pile, and a large rotational force acts during rotation and press-fitting. Therefore, the groove portion of the joint pipe needs to have a certain degree of strength. Strength can be ensured if a thick steel pipe is used as the material of the joint pipe, but if the part is thick enough not to have a large force, the material is wasted. About this, if the tube wall part constituting the groove part is a thickening part, when the groove part is plastically deformed from the raw steel pipe by hot deformation or the like, the thickening can be performed at the same time. The groove portion can be easily used as a thickened portion. In addition, since the thickening portion is processed together when the groove portion is plastically deformed, highly accurate and highly reliable processing can be performed.

  In the present invention, a reinforcing plate in which an intermediate portion in the plate width direction is welded in contact with the outer bottom surface of the groove-shaped portion and both ends are welded to the inner surface of the joint tube may be provided in the joint tube. The strength of the groove portion with respect to the rotational torque can be ensured also by welding of such a reinforcing plate. Although welding of the reinforcing plate is necessary, since it can be performed by factory welding, highly reliable welding can be easily performed.

  The joint structure of the rotary press-fit type steel pipe pile according to the present invention is a connection type rotary press-fit type steel pipe pile that is joined with a steel pipe pile made up of circular steel pipes one after the other and rotated against the ground. The joint structure is connected to each other, and is provided with a joint pipe that fits on the inner circumference of the lower steel pipe pile and the lower steel pipe pile connected to each other. In part, a groove portion that is recessed toward the inner diameter side is formed by plastically deforming the tube wall into a groove shape, and enters the groove shape portion of the joint pipe in the axial direction on the inner peripheral surface of the upper and lower steel pipe piles. Since there are provided engaging projections that engage in the circumferential direction, and the joint pipe is provided with a fall prevention projection that engages with the lower steel pipe pile and prevents the joint pipe from falling, Rotational transmission is possible, but on-site welding is not required, and mechanical connection can be made with simple work. Formation is simple, effect that the processing of the steel pipe pile itself requires little.

It is a fracture | rupture front which shows the placement process of the rotary press-fit type steel pipe pile to which the joint structure which concerns on 1st Embodiment of this invention is applied. (A) is the fracture | rupture front view of the joint structure of the same rotation press-fit type steel pipe pile, (B) is BB sectional drawing of the figure (A). (A) is a fractured front view of the joint structure in an exploded state, and (B) to (C) are a BB sectional view, a CC sectional view, and a DD arrow view of FIG. is there. It is explanatory drawing which shows an example of the processing method of the joint pipe in the joint structure. It is a fracture | rupture front view of the state which added the fall-off prevention tool in the joint structure of the same rotary press-fit type steel pipe pile. (A)-(C) are the fracture | rupture front in the joint structure of the rotary press-fit type steel pipe pile in other embodiment of this invention, a fracture | rupture side view, and VV sectional drawing of the same figure (A), respectively. (A) is a fractured front view of the joint structure in an exploded state, and (B) to (C) are a BB sectional view, a CC sectional view, and a DD arrow view of FIG. is there.

  A first embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 1, this rotary press-fit type steel pipe pile has a joint structure in which a plurality of steel pipe piles 1 each made of a circular steel pipe are successively joined up and down, and the lower end of the steel pipe pile 11 is conical at the tip 1a. In the connection-type rotary press-fit steel pipe pile 10 that is press-fitted while rotating with respect to the ground G, the joint structure that connects the upper and lower steel pipe piles 1 to each other has the spiral tip blade 2. The tip blade 2 is not necessarily provided.

  The pile driving machine 20 includes, for example, a pillar 22 provided on a travelable pile driving machine main body 21, and a pile head that holds the upper end of the rotary press-fit steel pipe pile 10 on a lifting body 23 that can be moved up and down along the pillar 22. What provided the holding tool 24 is used. The column 22 rotates the pile head gripping tool 24 with respect to the lifting body 23 and a lifting drive source 25 such as a hydraulic cylinder that applies pressure and pulling force to the rotary press-fit steel pipe pile 10 by moving the lifting body 23 up and down. And a rotary drive source (not shown) such as a hydraulic motor or an electric motor that rotates the rotary press-fit steel pipe pile 10. The rotational drive source can switch the rotational direction in the forward and reverse directions.

  As shown in FIGS. 2 and 3, this joint structure is provided with a joint pipe 3 that fits to the inner periphery of the lower steel pipe pile 1 </ b> A and the lower steel pipe pile 1 </ b> B connected to each other. The joint pipe 3 is provided with a groove portion 5 that is recessed in the inner diameter side in which the tube wall is plastically deformed into a groove shape in a part of the circumferential direction over the entire length in the axial direction, and from the upper steel pipe pile 1A. A steel pipe pile receiving rod 4 for transmitting a downward axial load to the side steel pipe pile 1B is provided in the center of the joint pipe length direction. The steel pipe pile receiving rod 4 also serves as a drop prevention protrusion for preventing the joint pipe 3 from dropping with respect to the lower steel pipe pile 1B. On the upper and lower steel pipe piles 1A and 1B, engaging protrusions 6 that enter the groove portion 5 of the joint pipe 3 in the axial direction and engage in the circumferential direction are provided on a part of the inner peripheral surface in the circumferential direction. Provide each.

The joint pipe 3 is obtained by processing a steel pipe. The pipe wall portion constituting the groove portion 5 of the joint pipe 3 is a thickened portion that is thicker than the other pipe wall portions in the joint pipe 3. The cross-sectional shape of the groove-shaped portion 5 is an isosceles trapezoidal shape in the illustrated example, but may be rectangular or arcuate.
The joint pipe 3 having the groove-shaped portion 5 which becomes the thickening processed portion in such a groove shape can be manufactured as shown in FIG. 4, for example. First, as shown to the same figure (A), the circular steel pipe W used as a raw material is prepared, As this figure steel pipe W is shown in the same figure (B), the thickening part Wa is provided in a part of circumferential direction. Thickening processing is performed on the steel pipe W1 with the thickened portion. In this thickening process, the inner and outer molds (not shown) having the forming surface along the inner peripheral surface and the outer peripheral surface after the thickening process in a state where the raw steel pipe W is heated by high frequency induction heating or the like. ) Etc., and the diameter is reduced so that the steel material of the tube wall is biased to a part in the circumferential direction. The thickened portion Wa has, for example, a cross-sectional shape in which the center of the thickened portion circumferential region is the thickest, gradually becomes thinner on both sides thereof, and both edges of the thickened portion circumferential region are thinnest. By forming the thickened portion Wa of the steel pipe W1 with the thickened portion thus processed into a groove shape by a forming die or the like in a heated state, a groove shape that becomes a thickened portion as shown in FIG. A joint pipe 3 having a portion 5 is provided. The step of processing the thickened portion Wa into a groove shape may be performed subsequent to the thickening step until the thickened portion Wa returns to room temperature, and the steel pipe W1 with the thickened portion is stored. The groove forming may be performed completely independently of the thickness increasing step. Further, the joint pipe 3 having the groove-shaped portion 5 formed of the thickened portion may be subjected to the thickening processing simultaneously with the processing of the groove-shaped portion 5 from the steel pipe of the circular steel pipe W that is the material.
In addition, the joint pipe 3 having the groove-shaped portion 5 is not limited to a steel pipe but may be a cast product such as cast iron or cast steel.

  The steel pipe pile receiver 4 is formed by fitting a ring member obtained by cutting a steel pipe short into the joint pipe 3 and joining the joint pipe 3 to the joint pipe 3 by fillet welding or the like, or winding a strip-shaped steel material around the outer circumference of the joint pipe 3. Joined by fillet welding or the like. At the place where the groove portion 5 of the joint pipe 3 is formed, the steel pipe pile receiving rod 4 is provided over the groove portion 5, that is, along the circular shape that becomes the outer peripheral surface of the joint pipe 3. The thickness of the steel pipe pile receiving rod 4 is thicker than the thickness of the pipe wall of the joint pipe 3, and is a thickness protruding from the outer peripheral surfaces of the steel pipe piles 1A and 1B fitted to the joint pipe 3. In addition to welding, the joint pipe 3 of the steel pipe pile receiving rod 4 may be joined by one-side tightening rivets (not shown) called bolts / nuts, blind bolts, one-side bolts, or the like.

  The engaging projections 6 provided on the upper and lower steel pipe piles 1A and 1B are obtained by joining straight rod-like members to the steel pipe piles 1A and 1B by fillet welding or the like. The engaging protrusion 6 has a rectangular cross-sectional shape in the illustrated example, but may have a round bar shape or the like.

  In addition, as shown in FIG. 5, you may provide the drop prevention tool 7 between the upper steel pipe pile 1A and the joint pipe 3, and between the lower steel pipe pile 1B and the joint pipe 3. The drop-off prevention tool 7 is used to prevent the joint pipe 3 and the steel pipe piles 1A and 1B from coming out of each other unexpectedly during construction. The drop-off prevention tool 7 is composed of, for example, a bolt or a pin that is provided in alignment with the pipe wall of the steel pipe piles 1A and 1B and the pipe wall of the joint pipe 3 and is inserted between the insertion holes 8 and 9. In the illustrated example, the drop-off prevention tool 7 is a bolt, and is attached by screwing into a nut 11 that is welded in alignment with the insertion hole 9 on the inner surface of the joint pipe 3. In addition to preventing accidental dropout, the dropout prevention tool 7 is also used for pulling out the steel pipe pile 1 when the tip blade 2 is not provided on the steel pipe pile 11 at the tip of FIG.

  Next, the pile driving work will be described. The steel pipe pile 11 at the lower end in FIG. 1 is prepared as having an engaging projection 6 at the upper end. The other steel pipe piles 1 are prepared on the assumption that the engaging protrusions 6 are provided on the upper and lower ends. Each steel pipe pile 1 to be connected is sequentially press-fitted into the ground by a pile driving machine 20 while being rotated. At this time, when the lower steel pipe pile 1B is press-fitted into the ground to a height suitable for connection work, the upper steel pipe pile 1A is connected.

In this connection work, the lower part of the joint pipe 3 is fitted to the upper end of the lower steel pipe pile 1B, and the lower end of the upper steel pipe pile 1A is fitted to the upper part of the joint pipe 3. This fitting is performed by the relative axial movement of the steel pipe piles 1A and 1B and the joint pipe 3, but at the time of this fitting, the upper and lower steel pipe piles are engaged in the groove portion 5 of the joint pipe 3. The protrusion 6 is inserted. In this connected state, the pile driving machine 20 applies pressure input while rotating the upper steel pipe pile 1A.
At this time, the pressure input acting on the steel pipe pile 3 and the downward compressive force due to the load of the upper structure (not shown) are transmitted through the axial load transmitting portion including the steel pipe pile receiving rod 4 of the joint pipe 3. . The rotation applied to the upper steel pipe pile 1A is caused by the engagement between the engagement protrusion 6 of the upper steel pipe pile 1A and the groove portion 5, and the engagement protrusion 6 of the groove portion 5 and the lower steel pipe pile 1B. The engagement is transmitted through the upper and lower engaging protrusions 6 and the groove-shaped portion 5 by engagement. Since it is the engagement between the groove-shaped portion 5 and the engaging protrusion 6 that enters the groove-shaped portion 5, rotation transmission in both forward and reverse directions is possible. Since it is possible to transmit rotation in both forward and reverse directions, if the pile driving machine 20 makes the reverse rotation, the steel pipe pile is lifted by the reverse rotation of the tip blade 2 at the lower end of the pile, and the steel pipe pile 1 can be pulled out.

  According to the joint structure of this configuration, bidirectional rotation transmission is possible in this way, but the fitting between the joint pipe 3 and the steel pipe piles 1A and 1B and the steel pipe pile 1A to the groove portion 5 of the joint pipe 3 It is only necessary to insert / remove the 1B engagement protrusion 6, no on-site welding is required, and mechanical connection can be made by a simple operation. Moreover, it is only necessary to provide the engagement projection 6 in the steel pipe pile 1, and for example, the processing of the steel pipe pile itself is small as compared with the case of welding an annular joint material over the entire circumference of the end of the steel pipe pile. The joint pipe 3 requires processing of the groove portion 5 and processing of an axial load transmitting portion such as the steel pipe pile receiving rod 4. However, the groove portion 5 is formed on a part of a short steel pipe which is a material of the joint pipe 3. Since it only needs to be plastically processed, it can be easily processed, unlike those processed into long steel pipe piles. Moreover, although the steel pipe pile receiving rod 4 is provided by welding of a ring member or the like, since it can be performed by factory welding, processing such as highly reliable welding can be performed.

  Further, the groove portion 5 of the joint pipe 3 is engaged with the engagement protrusions 6 of the steel pipe piles 1A and 1B, and a large rotational force acts upon rotation and press-fitting. Therefore, the groove portion 5 of the joint pipe 3 needs to have a certain degree of strength. Strength can be ensured if a thick steel pipe is used as the material of the joint pipe 3, but if the part where the large force does not act is made thick, the material is wasted. In this embodiment, since the tube wall portion constituting the groove portion 5 is a thickened portion, when the groove portion 5 is plastically deformed from a raw steel pipe by hot deformation or the like, the thickening is performed simultaneously. Therefore, the groove portion 5 can be easily used as a thickened portion. Further, since the thickened portion is processed together when the groove portion 5 is plastically deformed, highly accurate and reliable processing can be performed.

6 and 7 show another embodiment of the present invention. This embodiment is the same as the first embodiment shown in FIGS. 1 to 5 except for the matters specifically described. In this first embodiment, the joint structure of the rotary press-fit type steel pipe pile is replaced with a configuration in which the groove portion 5 is reinforced as a thickened portion, and the groove portion 5 has the same thickness as the other portions of the steel pipe pile 3. The reinforcing plate 12 is provided. The reinforcing plate 12 is made of a steel plate or the like, and is welded in the joint tube 3 with the middle portion in the plate width direction in contact with the outer bottom surface 5a of the groove portion 5 and both ends welded to the inner surface of the joint tube 3 at the weld portion 13. Has been. In this example, two reinforcing plates 12 are provided at two locations on the upper and lower sides of the joint pipe 3, and the respective reinforcing plates 12 are provided at height positions where the engaging protrusions 6 of the groove portion 5 are located. It has been. Note that the reinforcing plate 12 may be a single sheet that is wide in the vertical direction, or three or more.
Further, in this embodiment, the steel pipe pile receiving rod 4 in the example of FIG. 2 is not provided, and a drop prevention protrusion 15 that engages with the engagement protrusion 6 of the lower steel pipe pile 1B is provided in the groove portion 5. It has been. The fall prevention protrusion 15 is a means for preventing the joint pipe 3 from dropping with respect to the lower steel pipe pile 1B by engagement with the engagement protrusion 6. For example, a rod-shaped steel material having a rectangular cross section is used as a groove. It is joined in the shape part 5 by fillet welding or the like.

  In the case of this embodiment, at the time of connection work, the joint pipe 3 is inserted into the lower steel pipe pile 1B until the axial load transmission protrusion 15 is engaged with the engaging protrusion 6 of the lower steel pipe pile 1B. Further, the upper steel pipe pile 1 </ b> A is inserted into the joint pipe 3 until the engagement protrusion 6 is engaged with the axial load transmission protrusion 15 of the joint pipe 3. The downward axial load transmitted from the upper steel pipe pile 1A to the lower steel pipe pile 1B by the pressure input at the time of pile driving and the weight of the upper structure after pile driving is between the end faces of the upper and lower steel pipe piles 1A and 1B. Directly transmitted.

  In this embodiment, the groove portion 5 is reinforced by welding the reinforcing plate 12. However, the strength of the groove portion 5 with respect to the rotational torque can also be secured. Although welding of the reinforcing plate 12 is necessary, since it can be performed by factory welding, highly reliable welding can be easily performed. Further, the steel pipe pile receiving rod shown in FIG. 2 is not provided, and the load transmission in the vertical direction is performed directly between the end faces of the upper and lower steel pipe piles 1A and 1B, so that the configuration is simple and the manufacture is easy.

  In addition, in 1st Embodiment shown in FIGS. 1-5, ie, embodiment which used the groove-shaped part 5 of the joint pipe 3 as the thickening process part, the steel pipe pile receiving rod 4 is abbreviate | omitted, and the upper and lower steel pipe piles 1A and 1B of FIG. You may make it transmit the load of an up-down direction directly between end surfaces. In that case, it is necessary to provide a fall prevention projection that prevents the joint pipe 3 from dropping with respect to the lower steel pipe pile 1B, such as providing the fall prevention projection 15 of the embodiment of FIGS. . Further, in the embodiment in which the groove-shaped portion 5 shown in FIGS. 6 and 6 is reinforced with the reinforcing plate 12, the steel pipe pile receiving rod 4 in the first embodiment may be provided instead of providing the drop preventing projection 15.

1A, 1B ... Steel pipe pile 2 ... Tip blade 3 ... Joint pipe 4 ... Steel pipe pile receptacle (fall prevention protrusion)
5 ... Groove-shaped part 6 ... Engagement protrusion 12 ... Reinforcement plate 15 ... Fall prevention protrusion

Claims (5)

In a connection type rotary press-fit type steel pipe pile that presses the steel pipe piles made of circular steel pipes one after the other in turn and presses against the ground, the joint structure connects the upper and lower steel pipe piles to each other,
A joint pipe that fits to the inner circumference of the lower steel pipe pile and the upper part of the lower steel pipe pile connected to each other is provided, and the pipe wall is grooved in a part of the circumferential direction of the joint pipe. A groove portion that is recessed toward the inner diameter side that has been plastically deformed is provided, and an engagement protrusion that engages in the circumferential direction by entering the groove portion of the joint pipe in the axial direction on the inner peripheral surface of the upper and lower steel pipe piles. A joint structure for a rotary press-fit type steel pipe pile, wherein a drop prevention protrusion is provided on each of the joint pipes to prevent the joint pipe from falling by engaging with a lower steel pipe pile.   The joint structure of the rotary press-fit type steel pipe pile according to claim 1, wherein the steel pipe pile at the lower end among the steel pipe piles successively connected to the upper and lower sides has a spiral tip blade.   In Claim 1 or Claim 2, the said fall prevention protrusion is provided in the middle perimeter of the length direction of the above-mentioned joint pipe, and intervenes between the lower end face of an upper steel pipe pile, and the upper end face of a lower steel pipe pile. Joint structure of a rotary press-fit type steel pipe pile that is a steel pipe pile receiver.   4. The thickened portion according to claim 1, wherein a tube wall portion constituting the groove-shaped portion of the joint pipe is thicker than other pipe wall portions in the joint pipe. The joint structure of a rotary press-fit type steel pipe pile. 4. The method according to claim 1, wherein an intermediate portion in the plate width direction is welded to the outer bottom surface of the groove portion and both ends are welded to the inner surface of the joint pipe. The joint structure of a rotary press-fit type steel pipe pile with a reinforcing plate.

Images