JP2022177726A - Connection structure of steel pipe pile, and method for manufacturing steel pipe pile - Google Patents

Abstract

To provide a connection structure and a manufacturing method of a steel pipe pile which can appropriately connect vertically arranged steel pipe piles through a sleeve.SOLUTION: A first cylindrical joint part 30 is provided on a lower side steel pipe pile 10, and a second cylindrical joint part 40 is provided on an upper side steel pipe pile 20. The first joint part 30 extends toward the side of the second joint part 40 in an axial direction from the radial outside out of the upper end of the lower side steel pipe pile 10. The second joint part 40 is provided in the radial outside of the upper side steel pipe pile 20. A first projection 32 is formed at the end of the first joint part 30, and a second recess 43 is formed at the end of the second joint part 40. In a state where the first projection 32 is fit into the second recess 43, the lower side steel pipe pile 10 and the upper side steel pipe pile 20 are separated from one another, and the lower side steel pipe pile 10 and the upper side steel pipe pile 20 become concentric. A sleeve 50 is fit into each of the through holes 34 and 44 formed in each of the joint parts 30 and 40.SELECTED DRAWING: Figure 3

Description

TECHNICAL FIELD The present invention relates to a steel pipe pile connection structure and manufacturing method.

Pile foundations are used to support structures when building structures on soft ground. Pile foundations require the tip of a cylindrical steel pipe pile to reach the bearing layer under the soft ground. Therefore, there is a construction method in which a steel pipe pile equipped with an excavation blade is buried in the ground while being rotated, the lower end of a new steel pipe pile is connected to the upper end of the buried steel pipe pile, and the connected steel pipe pile is buried while being rotated. used.

Steel pipes placed above and below without welding at the site where the steel pipe piles are buried in order to connect the previously buried steel pipe pile and the steel pipe pile placed above the steel pipe pile. Patent Document 1 discloses a technique for connecting ends of piles.

To explain this technology, a cylindrical inside cylinder is joined to the upper end of the lower steel pipe pile, and a cylindrical outside cylinder that is fitted to the inside cylinder from the outside is joined to the lower end of the upper steel pipe pile. ing. In a state in which the outside cylinder and the inside cylinder are fitted together, the lower end surface of the upper steel pipe pile and the upper end surface of the inside cylinder abut. Each of the inside cylinder and the outside cylinder is formed with a through hole penetrating from the outer peripheral surface of the outside cylinder to the inner peripheral surface of the inside cylinder in this contact state.

A truncated cone-shaped taper lock portion is fitted in the through hole of each cylinder. Thereby, the inside cylinder and the outside cylinder are connected. When the upper steel pipe pile is rotated in the connected state, the rotational torque acting on the upper steel pipe pile is transmitted to the lower steel pipe pile, and the lower steel pipe pile is also rotated.

Japanese Patent No. 6243814

The flatness of the axial end face of the steel pipe pile can be increased due to processing accuracy or the like in the manufacturing stage of the steel pipe pile. In this case, the central axis of the through hole of the inside cylinder that abuts on the lower end surface of the upper steel pipe pile may deviate from the central axis of the through hole of the outside cylinder. If the central axis of each through-hole is misaligned, there is a concern that it will be difficult to insert the taper lock portion into the through-hole. In this case, there is a concern that the connection between the upper and lower steel pipe piles via the taper lock portion may not go well.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a steel pipe pile connection structure and a steel pipe pile manufacturing method that can properly connect steel pipe piles arranged vertically. .

The present invention relates to a steel pipe pile connection structure that connects ends of cylindrical steel pipe piles arranged vertically,
In the first steel pipe pile which is one of the steel pipe piles arranged above and below, a cylindrical shape provided so as to be concentric with the first steel pipe pile on either side of the radial direction inside or outside of the first steel pipe pile a first joint portion of
The second steel pipe pile, which is the other of the vertically arranged steel pipe piles, is concentrically with the second steel pipe pile on the same side as the first joint part in the radial direction inside and outside of the second steel pipe pile. a cylindrical second joint portion provided;
with
The first joint portion extends beyond the axial end face of the first steel pipe pile toward the second joint portion,
The second joint portion is provided at a position retreated from the axial end surface of the second steel pipe pile in the axial direction to the opposite side of the first steel pipe pile,
A convex portion protruding toward the second joint portion in the axial direction is formed at an end portion of the first joint portion,
An end portion of the second joint portion is formed with a concave portion that is concave in an axial direction opposite to the first joint portion side and that is fitted to the convex portion,
In a state in which the portion of the second steel pipe pile closer to the first joint portion than the second joint portion is fitted into the first joint portion, and the convex portion is fitted into the recess, the first The steel pipe pile and the second steel pipe pile are spaced apart, and the first steel pipe pile and the second steel pipe pile are concentric,
A through hole is formed that penetrates each of the first joint portion and the second steel pipe pile in a radial direction in a state where the convex portion is fitted in the concave portion,
In order to connect the first joint portion and the second steel pipe pile, a sleeve is provided that is fitted into the through hole so as to straddle the through holes of the first joint portion and the second steel pipe pile.

In the present invention, the portion of the second steel pipe pile closer to the first joint than the second joint serves as a guide portion for fitting the protrusion of the first joint into the recess of the second joint. The 1st steel pipe pile and the 2nd steel pipe pile are estranged in the state where this guide part was fitted in the 1st joint part and the convex part was fitted in the crevice. That is, the axial end faces of the first steel pipe pile and the second steel pipe pile are not in contact with each other. For this reason, due to the fitting between the convex portion of the first joint portion and the concave portion of the second joint portion, the axis of the second steel pipe pile with respect to the first joint portion is not affected by the flatness of the axial end surface of the steel pipe pile. A relative position in the direction is determined. As a result, it is possible to suppress the deviation between the central axis of the through hole of the first joint portion and the central axis of the through hole of the second steel pipe pile, and prevent the sleeve from becoming difficult to insert into the through hole. As a result, the upper and lower steel pipe piles can be appropriately connected via the sleeve.

Moreover, in this invention, in addition to the structure by which the convex part of a 1st joint part is fitted by the recessed part of a 2nd joint part, a 1st joint part and a 2nd steel pipe pile are firmly connected with a sleeve. As a result, the rotational torque can be borne by the sleeve in addition to the first and second joint portions. As a result, it is also possible to prevent the connecting portions of the steel pipe piles arranged vertically from being greatly deformed or damaged.

The front view of a pair of steel pipe piles arrange|positioned up and down. The front view of the connection part of the fitted steel pipe pile. FIG. 2 is a vertical cross-sectional view of a connecting portion of fitted steel pipe piles (cross-sectional view along line 3-3 in FIG. 2); FIG. 4 is a vertical cross-sectional view of a connecting portion of steel pipe piles before being fitted together; The perspective view of a 1st joint part. The figure which looked at the 1st joint part from the axial direction. The perspective view of a 2nd joint part. The figure which looked at the 2nd joint part from the axial direction. 9-9 line cross-sectional view of FIG. 3 in a state where the nut cover is provided on the inner peripheral surface of the upper steel pipe pile and the sleeve is fitted into the through hole. The figure which shows a sleeve. The figure which shows the procedure of the connection method of a steel pipe pile. The front view of the connection part of the fitted steel pipe pile which concerns on other embodiment. The longitudinal cross-sectional view of the connection part of the steel pipe pile before being fitted which concerns on other embodiment. The longitudinal cross-sectional view of the connection part of the fitted steel pipe pile which concerns on other embodiment.

EMBODIMENT OF THE INVENTION Hereinafter, one Embodiment which actualized the connection structure of the steel pipe pile which concerns on this invention is described, referring drawings. As shown in FIG. 1, the connection structure connects a steel pipe pile that is first buried in the ground and a steel pipe pile that is subsequently buried after that steel pipe pile. Below, among the paired steel pipe piles arranged vertically, the one arranged on the lower side is called the lower steel pipe pile 10 and the one arranged on the upper side is called the upper steel pipe pile 20 . An excavation bit DB and an expanding wing DW are provided at the lower end of the lowermost steel pipe pile among the plurality of steel pipe piles arranged in the vertical direction. The expanded wing DW has a semi-disc shape, and is provided in plurality (two are illustrated) at the lower end of the steel pipe pile.

As shown in FIGS. 2 to 4, the lower steel pipe pile 10 and the upper steel pipe pile 20 are cylindrical. The outer diameter dimension of the lower steel pipe pile 10 and the outer diameter dimension of the upper steel pipe pile 20 are the same. Moreover, the thickness dimension of the lower steel pipe pile 10 and the thickness dimension of the upper steel pipe pile 20 are the same.

The connection structure of the lower steel pipe pile 10 and the upper steel pipe pile 20 includes a first joint portion 30 and a second joint portion 40 . The first joint portion 30 is provided at the upper end of each of the steel pipe piles 10 and 20 , and the second joint portion 40 is provided at the lower end of each of the steel pipe piles 10 and 20 . In addition, since the wing expansion DW etc. are provided in the lower end part of the steel-pipe pile of the lowest side among several steel-pipe piles arrange|positioned in the up-down direction, the 2nd joint part 40 is not provided.

The first joint portion 30 is a member made of steel. The first joint portion 30 includes a cylindrical portion 31 and a first convex portion 32, as shown in FIGS. The inner diameter dimension of the cylindrical portion 31 is slightly larger than the outer diameter dimension of the lower steel pipe pile 10 . The upper end of the lower steel pipe pile 10 is welded to the lower end of the cylindrical portion 31 while the cylindrical portion 31 is fitted to the upper end of the lower steel pipe pile 10 from the outside. Thereby, the first joint portion 30 is concentric with the lower steel pipe pile 10 . The thickness dimension of the first joint portion 30 is larger than the thickness dimension of the lower steel pipe pile 10 .

The first convex portion 32 extends upward from the axial upper end of the cylindrical portion 31 . A plurality of first protrusions 32 (two are illustrated) are formed side by side at regular intervals in the circumferential direction of the first joint portion 30 . In the first joint portion 30 , first concave portions 33 are provided between the first convex portions 32 arranged in the circumferential direction. In the present embodiment, as shown in FIG. 6, the length dimension in the circumferential direction of the first convex portion 32 is set to 1/4 of the length dimension in the circumferential direction of the cylindrical portion 31 . For this reason, the length dimension in the circumferential direction of the first concave portion 33 is also set to 1/4 of the length dimension in the circumferential direction of the cylindrical portion 31 .

The second joint portion 40 is a member made of steel. The outer diameter dimension of the second joint portion 40 and the outer diameter dimension of the first joint portion 30 are the same. The thickness dimension of the second joint portion 40 is larger than the thickness dimension of the upper steel pipe pile 20 and the same as the thickness dimension of the first joint portion 30 . As shown in FIGS. 2 to 4, 7, and 8, the second joint portion 40 includes an annular portion 41 and a second convex portion 42. As shown in FIGS. The upper end portion of the upper steel pipe pile 20 is welded to the upper steel pipe pile 20 in a state where the ring portion 41 is fitted from the outside to a position retreated upward from the axial lower end of the upper steel pipe pile 20. Thereby, the second joint portion 40 is concentric with the upper steel pipe pile 20 .

The second convex portion 42 extends downward from the axial lower end of the annular portion 41 . The second protrusions 42 are arranged at regular intervals in the circumferential direction of the second joint part 40 and formed in the same number as the first protrusions 32 . In the second joint portion 40 , second concave portions 43 are provided between the second convex portions 42 arranged in the circumferential direction. The dimension of the recess in the axial direction of the second concave portion 43 with respect to the lower end surface of the second joint portion 40 is the same as the dimension of the axial projection of the first convex portion 32 with respect to the upper end surface of the cylindrical portion 31 .

In the present embodiment, as shown in FIG. 8, the circumferential length dimension of the second convex portion 42 is set to 1/4 of the circumferential length dimension of the annular portion 41 . Therefore, the length dimension in the circumferential direction of the second concave portion 43 is also set to 1/4 of the length dimension in the circumferential direction of the annular portion 41 . That is, the length dimension in the circumferential direction of the second protrusion 42 and the second recess 43 is the same as the length dimension in the circumferential direction of the first protrusion 32 and the first recess 33 .

As shown in FIGS. 5 and 6, the circumferential side surface of the first protrusion 32 is a first inclined side surface 32a. As shown in FIG. 6, the first inclined side surface 32a lies on a plane that passes through the central axis O of the first joint portion 30 and is parallel to the direction in which the central axis O extends. Further, as shown in FIGS. 7 and 8, the side surface of the second protrusion 42 in the circumferential direction is a second inclined side surface 42a. As shown in FIG. 8, the second inclined side surface 42a lies on a plane that passes through the central axis O of the second joint portion 40 and is parallel to the direction in which the central axis O extends. As a result, in the process of fitting the first convex portion 32 into the second concave portion 43 , axial misalignment of the upper steel pipe pile 20 with respect to the lower steel pipe pile 10 can be reduced.

With reference to FIGS. 1, 3 and 4, the process of joining the joint portions 30 and 40 to the steel pipe pile among the manufacturing processes of the steel pipe pile will be described. 3 and 4 show respective ends of two steel pipe piles 10 and 20. Of one steel pipe pile, the first end side is the lower steel pipe pile 10 shown on the lower side in the figure. , and the second end side corresponds to the end of the upper steel pipe pile 20 shown on the upper side in the figure.

In the joining step, a first joint portion 30 is joined to the first end side of the steel pipe pile so as to be concentric with the steel pipe pile, and a second joint portion 30 is joined to the second end side of the steel pipe pile so as to be concentric with the steel pipe pile. The part 40 is joined. Specifically, the distance LA in the axial direction from the end face 11 on the first end side of the steel pipe pile to the tip of the first protrusion 32 is the distance from the end face 21 on the second end side of the steel pipe pile to the base end of the second recess 43. The first joint portion 30 and the second joint portion 40 are joined to the radially outer side of the steel pipe pile so as to be longer than the distance LB in the axial direction.

As shown in FIGS. 3 and 4 , the inner diameter dimension of the first joint portion 30 is slightly larger than the outer diameter dimension of the upper steel pipe pile 20 . This allows the first joint portion 30 to be loosely fitted to the upper steel pipe pile 20 . A portion of the upper steel pipe pile 20 below the second joint portion 40 serves as a guide portion for fitting the first convex portion 32 to the second concave portion 43 . This guide portion is fitted into the cylindrical portion 31 of the first joint portion 30 , and the first projection 32 is fitted into the second recess 43 . As a result, the upper end surface of the first convex portion 32 is in close contact with the second concave portion 43, and the first inclined side surface 32a is in close contact with the second inclined side surface 42a. In this state, the upper end surface 11 of the lower steel pipe pile 10 is separated from the lower end surface 21 of the upper steel pipe pile 20 .

An outer through hole 34 is formed in the cylindrical portion 31 of the first joint portion 30 . A plurality of outer through-holes 34 (four are exemplified) are formed along the circumferential direction of the first joint portion 30 at regular intervals. Each outer through-hole 34 has the same shape and is formed at the same position in the axial direction of the first joint portion 30 .

An inner through hole 44 is formed at the lower end of the upper steel pipe pile 20 . The inner through-holes 44 are arranged at equal intervals in the circumferential direction of the upper steel pipe pile 20 and are formed in the same number as the outer through-holes 34 . Each inner through hole 44 has the same shape and is formed at the same position in the axial direction of the upper steel pipe pile 20 . The first protrusion 32 is fitted into the second recess 43 so that one of the outer through holes 34 and one of the inner through holes 44 are aligned. As a result, four through holes 34 and 44 that penetrate from the outer peripheral surface of the first joint portion 30 to the inner peripheral surface of the upper steel pipe pile 20 are formed.

Incidentally, the outer through-holes 34 and the inner through-holes 44 may be formed by, for example, the method described below. In a factory, the outer through-hole 34 is formed in the first joint portion 30 by drilling the first joint portion 30 before being joined to the steel pipe pile with a processing machine (for example, a hole saw or a drill). And the 1st joint part 30 in which the outer through-hole 34 was formed is joined to a steel pipe pile by welding. Further, in a factory, after the second joint portion 40 is joined to the steel pipe pile by welding, the steel pipe pile to which the second joint portion 40 is joined is drilled with a processing machine, thereby forming an inner through hole in the steel pipe pile. form 44; At this time, for example, the inner through hole 44 may be formed based on the position of the second joint portion 40 with respect to the steel pipe pile.

By fitting the first convex portion 32 of the first joint portion 30 and the second concave portion 43 of the second joint portion 40, the flatness of the axial end surfaces 11 and 21 of the steel pipe piles 10 and 20 does not affect the flatness. , the relative position in the axial direction of the upper steel pipe pile 20 with respect to the first joint portion 30 is determined. Thereby, the deviation between the center axis of the outer through hole 34 of the first joint portion 30 and the center axis of the inner through hole 44 of the upper steel pipe pile 20 can be suppressed, and the inner peripheral surfaces of the through holes 34, 44 are the first The outer peripheral surface of the joint portion 30 can be made continuous to the inner peripheral surface of the upper steel pipe pile 20 as much as possible. As a result, it is possible to prevent the sleeves 50 described later from being difficult to insert into the through holes 34 and 44 .

In this embodiment, each through hole 34, 44 has a rectangular shape elongated in the circumferential direction of each steel pipe pile 10, 20. As shown in FIG. The central axis of the outer through-hole 34 extends in the radial direction of the first joint portion 30, and the outer through-hole 34 is formed so that the opening area decreases as it goes radially inward. Further, the central axis of the inner through-hole 44 extends in the radial direction of the upper steel pipe pile 20, and the inner through-hole 44 is formed so that the opening area becomes smaller as it goes radially inward.

As shown in FIGS. 9 and 10, the coupling structure comprises a sleeve 50. As shown in FIG. In this embodiment, the sleeve 50 is a member made of steel and is fitted into the through holes 34 and 44 . The sleeve 50 has a truncated pyramid shape whose height direction is the radial direction of the steel pipe piles 10 and 20 and whose cross-sectional area decreases toward the radially inner side of the steel pipe piles 10 and 20 . That is, when the radially inner end face of the sleeve 50 is the leading end face 52 and the radially outer end face is the trailing end face 53, the leading end face 52 and the trailing end face 53 are connected by four conical faces 54. The tip surface 52 is an arcuate surface that is recessed radially outward. The curvature of this arc surface and the curvature of the inner peripheral surface of the upper steel pipe pile 20 are the same. In addition, the rear end surface 53 is an arcuate surface that is convex radially outward. The curvature of this arc surface and the curvature of the outer peripheral surface of the first joint portion 30 are the same.

The cross section of the sleeve 50 has a rectangular shape elongated in the circumferential direction of the steel pipe piles 10 and 20 . The cross-sectional shape of the sleeve 50 is congruent with the through holes 34,44. Therefore, when the sleeve 50 is fitted into the through holes 34, 44, the four conical surfaces 54 of the sleeve 50 are in close contact with the inner peripheral surfaces of the through holes 34, 44, respectively. Thereby, the rotational torque acting on the upper steel pipe pile 20 can be accurately transmitted to the lower steel pipe pile 10 . In the cross section of the sleeve 50, the ratio of the length dimension in the lateral direction to the length dimension in the longitudinal direction can be set to 1:1.2 or 1:1.5, for example. Also, the corners of the sleeve 50 such as the periphery of the cone surface 54 may be chamfered (specifically, for example, C chamfer, R chamfer, or thread chamfer).

A central portion of the sleeve 50 is formed with a bolt insertion hole 51 penetrating in a direction orthogonal to the cross section of the sleeve 50 (that is, in the radial direction of the steel pipe piles 10 and 20). The length dimension of the sleeve 50 in the direction in which the bolt insertion hole 51 extends is substantially the same dimension as the total thickness dimension of the first joint portion 30 and the upper steel pipe pile 20 .

A bolt 60 is inserted through the bolt insertion hole 51 . The bolt 60 has a shaft portion 61 and a head portion 62 . A male thread is formed on the outer circumference of the shaft portion 61 . The bolt 60 is inserted through the bolt insertion hole 51 with the head portion 62 facing radially outward of the steel pipe piles 10 and 20 and the shaft portion 61 facing radially inward. The head 62 abuts the rear end face 53 of the sleeve 50 . A washer may be interposed between the head portion 62 and the rear end surface 53 . Further, the rear end surface 53 may be formed with a concave portion in which the head portion 62 of the bolt 60 is accommodated. As a result, the head portion 62 does not protrude from the outer peripheral surface of the first joint portion 30 .

As shown in FIGS. 6 and 8 , nut covers 70 are provided on the inner peripheral surface of the upper steel pipe pile 20 at positions corresponding to the inner through holes 44 . The nut cover 70 is made of steel and contains the nut 80 . The nut cover 70 serves to position the nut 80 screwed onto the shaft portion 61 and to restrict the rotation of the nut 80 .

The nut cover 70 has a base plate 71 . The first surface of the base plate 71 is a flat surface, and the second surface of the base plate 71 is an arcuate surface convex in the direction from the first surface to the second surface. The curvature of this arc surface is the same as the curvature of the inner peripheral surface of the upper steel pipe pile 20 .

The base plate 71 has a rectangular shape, specifically, a rectangular shape elongated in the circumferential direction of the upper steel pipe pile 20 . The length dimension of the base plate 71 in the circumferential direction of the upper steel pipe pile 20 is greater than the length dimension of the inner through-hole 44 in the circumferential direction of the upper steel pipe pile 20 . The circular arc surface of the base plate 71 and the inner peripheral surface of the upper steel pipe pile 20 are in contact with the base plate 71 straddling the inner through hole 44 in the circumferential direction of the inner through hole 44 . In this contact state, both ends of the base plate 71 in the longitudinal direction are welded to the inner peripheral surface of the upper steel pipe pile 20 . This increases the strength of the portion of the upper steel pipe pile 20 around the inner through hole 44 .

In this embodiment, the length dimension of the base plate 71 in the axial direction of the upper steel pipe pile 20 is greater than the length dimension of the inner through hole 44 in the axial direction of the upper steel pipe pile 20 . Thereby, the strength of the peripheral portion of the inner through-hole 44 of the upper steel pipe pile 20 is further enhanced.

As shown in FIG. 9 , a plate hole 71 a is formed in the central portion of the base plate 71 so as to penetrate the upper steel pipe pile 20 in the radial direction and through which the shaft portion 61 is inserted. The center axis of the plate hole 71a and the center axis of the inner through hole 44 are the same. The opening area of the plate hole 71a is smaller than the innermost opening area of the inner through holes 44 in the radial direction. Therefore, when the inner through-hole 44 is viewed from the radial direction of the upper steel pipe pile 20, the inner through-hole 44 is partially covered with a portion of the base plate 71 where the plate hole 71a is not formed. 9 shows only the base plate 71 of the nut cover 70. As shown in FIG. 2 to 4 and 8, illustration of the nut cover 70 is omitted.

As shown in FIG. 7 , the nut cover 70 includes a strut portion 72 , a plate portion 73 and a holding portion 74 . In the present embodiment, the strut portion 72, the plate portion 73 and the holding portion 74 are integrally constructed. The plate portion 73 is arranged with its plate surface facing the flat surface of the base plate 71 . Of the plate portions 73 , both end portions in the axial direction of the upper steel pipe pile 20 are each formed as a strut portion 72 bent radially outward of the upper steel pipe pile 20 . The tip of each strut 72 is welded to the flat surface of the base plate 71 . Each of the strut portions 72 has a holding portion 74 bent in the axial direction of the upper steel pipe pile 20 at both ends in the circumferential direction of the upper steel pipe pile 20 . A nut 80 is accommodated in a space surrounded by the base plate 71 , the strut portion 72 , the plate portion 73 and the holding portion 74 . This space is made slightly larger than the nut 80 so that a gap is formed between the nut cover 70 and the nut 80 . This gap makes it easier to screw the shaft portion 61 into the female thread of the nut 80 . A hole 75 is formed in the plate portion 73 to prevent the shaft portion 61 from interfering with the plate portion 73 . Also, in FIG. 9, the illustration of the support 72 and the like is omitted.

The nut 80 is enclosed in the nut cover 70 at the factory in a manner to be described below. Specifically, before welding the support 72 to the base plate 71 , the nut 80 is accommodated in the space surrounded by the support 72 , the plate 73 and the holding section 74 . Then, the base plate 71 is welded to the strut portion 72 . Thereby, the nut 80 is included in the nut cover 70 .

The nut cover 70 containing the nut 80 is welded to the inner peripheral surface of the steel pipe pile at the factory. This welding work is performed by inserting, for example, a welding rod for arc welding from an opening 22 (see FIG. 7) at the axial end of the steel pipe pile. Specifically, both ends of the base plate 71 in the longitudinal direction are welded to the inner peripheral surface of the steel pipe pile. In this case, the welding work can be performed more easily than in the case of welding the end farther from the opening 22 of the both ends of the base plate 71 in the short direction, and the efficiency of the welding work can be improved. be able to.

The base plate 71 is long in the circumferential direction of the upper steel pipe pile 20 . Therefore, the distance from the longitudinal end of the base plate 71 to the nut 80 can be increased. As a result, when welding the end portion of the base plate 71 , the influence of heat generated by welding on the nut 80 can be suppressed. This can prevent the material properties of the nut 80 from changing.

The steel pipe piles 10, 20 to which the joint portions 30, 40 are welded are transported to the site where the steel pipe piles are to be buried. A method of connecting the lower steel pipe pile 10 and the upper steel pipe pile 20 at the burial site will be described below with reference to FIG. 11 .

First, as shown in FIG. 11(A), the upper steel pipe pile 20 is fitted to the first joint portion 30 so that the positions of the inner through-hole 44 and the outer through-hole 34 are aligned with each other. The first convex portion 32 is fitted into the second concave portion 43 . Thereby, the lower steel pipe pile 10 and the upper steel pipe pile 20 are concentric.

Subsequently, the sleeve 50 is inserted into the through holes 34 and 44 until the tip surface 52 of the sleeve 50 abuts against the arcuate surface of the base plate 71 . As a result, the sleeve 50 is fitted into the through holes 34 and 44 and each conical surface 54 of the sleeve 50 is in close contact with the inner peripheral surfaces of the through holes 34 and 44 . Since the cross-sectional area of the sleeve 50 becomes smaller toward the inner side in the radial direction, the sleeve 50 can be easily inserted into the through holes 34 and 44 .

Subsequently, as shown in FIG. 11B, the bolt 60 is tightened with the head portion 62 of the bolt 60 facing radially outward of the steel pipe piles 10 and 20 and the shaft portion 61 facing radially inward. It is inserted through the insertion hole 51, and the tip of the shaft portion 61 is inserted into the female thread of the nut 80 via the plate hole 71a. Then, the bolt 60 is rotated clockwise to screw the male thread of the shaft portion 61 into the female thread of the nut 80 . At this time, the nut cover 70 prevents the nut 80 from co-rotating with the rotation of the bolt 60 .

The bolt 60 is further rotated to further screw the male thread of the shaft portion 61 into the female thread of the nut 80 . Thereby, as shown in FIG. 11C, the sleeve 50 is pressed radially inward by the head 62 of the bolt 60, and the first joint portion 30 and the upper steel pipe pile 20 are firmly fixed. As a result, the upper steel pipe pile 20 and the lower steel pipe pile 10 are firmly fixed.

According to the present embodiment described above, the relative position in the axial direction of the upper steel pipe pile 20 with respect to the first joint portion 30 is not affected by the flatness of the axial end surfaces 11 and 21 of the steel pipe piles 10 and 20. determined. As a result, the outer through-hole 34 of the first joint portion 30 and the inner through-hole 44 of the upper steel pipe pile 20 can be made coaxial, and it is possible to prevent difficulty in inserting the sleeve 50 into the respective through-holes 34 , 44 . As a result, the upper and lower steel pipe piles 10 and 20 can be properly connected via the sleeve 50 .

Since the lower steel-pipe pile 10 and the upper steel-pipe pile 20 are spaced apart, the transmission of force between the lower steel-pipe pile 10 and the upper steel-pipe pile 20 is mainly performed by the first joint portion 30 and the second joint portion 40. is done through In this case, the load concentrates on the first convex portion 32 of the first joint portion 30 and the second concave portion 43 of the second joint portion 40, and the first convex portion 32 and the second concave portion 43 are greatly deformed or damaged. There is concern that

In this regard, in the present embodiment, the sleeve 50 is in close contact with the inner peripheral surfaces of the outer through-hole 34 of the first joint portion 30 and the inner through-hole 44 of the upper steel pipe pile 20 . Therefore, the transmission of force between the lower steel pipe pile 10 and the upper steel pipe pile 20 can be carried by the sleeve 50 in addition to the first convex portion 32 and the second concave portion 43, and the rotational torque and axial load can be handled. can. Thereby, it is possible to prevent the first convex portion 32 and the second concave portion 43 from being largely deformed or damaged.

In the cross section of the sleeve 50, the length dimension of each steel pipe pile 10, 20 in the circumferential direction is larger than the length dimension of each steel pipe pile 10, 20 in the axial direction. As a result, when the upper steel pipe pile 20 rotates relative to the lower steel pipe pile 10 when burying the steel pipe pile, the length dimension of the sleeve 50 in the direction in which the rotational torque acts can be increased, and the sleeve 50 can withstand the external force. Strength can be increased. As a result, it is possible to prevent the sleeve 50 from being largely deformed or damaged.

The cross section of the sleeve 50 has a rectangular shape elongated in the circumferential direction of the steel pipe piles 10 and 20 . As a result, the cross-sectional area of the sleeve 50 can be increased compared to, for example, the case where the cross-section of the sleeve has an elliptical shape elongated in the circumferential direction. Thereby, the strength of the sleeve 50 can be further increased.

<Other embodiments>
It should be noted that the above embodiment may be modified as follows.

- The cross section of the sleeve and the shape of the through hole are not limited to a rectangular shape.

Moreover, the cross section of the sleeve and the shape of the through hole are not limited to the shape elongated in the circumferential direction of the steel pipe piles 10 and 20, and may be, for example, a square shape or a perfect circle shape. A sleeve having a perfectly circular cross-sectional shape has a truncated cone shape.

- As a sleeve, the area of a cross section may be constant in the radial direction of each steel pipe pile 10,20. In this case, for example, if the cross section is rectangular, the sleeve has a cuboid shape. Further, in this case, since a portion of the inner through-hole 44 is covered with the base plate 71 , the base plate 71 positions the sleeve when the sleeve 50 is inserted. This prevents the sleeve 50 from being inserted too much.

- The bolt insertion hole 51 may not be formed in the sleeve 50 . In this case, bolt 60, nut cover 70 and nut 80 are not required. In this case, for example, by applying an adhesive to the conical surface 54 of the sleeve 50 and inserting it into the through holes 34 and 44, the gap between the conical surface 54 of the sleeve 50 and the inner peripheral surfaces of the through holes 34 and 44 is reduced. An adhesive layer may be formed. This makes it difficult for the sleeve 50 to come off the through holes 34 and 44 , and the lower steel pipe pile 10 and the upper steel pipe pile 20 can be firmly connected.

- The cross-sectional shape of each sleeve 50 arranged in the circumferential direction may differ. For example, among the sleeves 50 arranged in the circumferential direction, at least one of the sleeves may have a cross section elongated in the circumferential direction of the steel pipe pile (for example, rectangular). In this case, for example, rectangular and square sleeves may alternate in the circumferential direction.

- Each through-hole 34 and 44 formed along with the circumferential direction may be formed in multiple rows in the axial direction. For example, when two rows are formed in the axial direction, the through holes in the first row are referred to as first through holes, and the through holes in the second row are referred to as second through holes. In this case, the second through-hole is a position shifted downward from the position of the first through-hole in the axial direction of each steel pipe pile 10, 20, and the first through-hole in the circumferential direction of each steel pipe pile 10, 20 may be formed at a position shifted from the position of . That is, the arrangement of the first through holes and the second through holes may be a so-called staggered arrangement.

・At the factory, the outer through-hole 34 of the first joint 30 and the inner through-hole 44 of the upper steel pipe pile 20 are coaxial under the condition that the temperature of each steel pipe pile and each joint becomes the reference temperature. Even if the through holes 34 and 44 are formed, inconvenience may occur for the reasons explained below. To explain with reference to FIG. 3 , the axial length of the portion of the upper steel pipe pile 20 below the annular portion 41 may change as the temperature of the upper steel pipe pile 20 changes. For example, due to the temperature rise of the upper steel pipe pile 20 , the upper steel pipe pile 20 may expand in the axial direction, and the upper side of the outer through-hole 34 may be blocked by the upper steel pipe pile 20 . On the other hand, due to the temperature drop of the upper steel pipe pile 20 , the upper steel pipe pile 20 may contract in the axial direction, and the lower side of the outer through-hole 34 may be blocked by the upper steel pipe pile 20 . If the outer through-hole 34 is blocked by the upper steel pipe pile 20, it becomes difficult to insert the sleeve 50.例文帳に追加

Therefore, as shown in FIG. 12, the axial length dimension of the inner through hole 45 in the upper steel pipe pile 20 is larger than the axial length dimension of the portion of the sleeve 50 that is inserted into the inner through hole 45. may be 12 omits illustration of the bolt insertion hole 51 of the sleeve 50, the bolt 60, the base plate 71, and the like.

According to the configuration shown in FIG. 12 , it is possible to prevent a part of the outer through-hole 34 from being blocked due to a change in temperature of the upper steel pipe pile 20, making it difficult to insert the sleeve 50 into the through-holes 34, 45. can be prevented. In this case, each conical surface 54 of the sleeve 50 in the circumferential direction of the upper steel pipe pile 20 is in close contact with the inner peripheral surface of the inner through hole 45 . Therefore, while the joint portions 30 and 40 bear axial loads, rotational torque can be transmitted from the upper steel pipe pile 20 to the lower steel pipe pile 10 via the sleeve 50 and the first joint portion 30 .

- Both sides of the base plate 71 may be flat surfaces. In this case, the tip surface 52 of the sleeve 50 should be flat.

- The 1st joint part 30 may be provided in the lower end part of a steel pipe pile, and the 2nd joint part 40 may be provided in the upper end part of a steel pipe pile.

- The 1st joint part and the 2nd joint part may be provided in the internal peripheral surface instead of the outer peripheral surface of a steel pipe pile. Hereinafter, differences from the connection structure shown in FIG. 4 and the like will be mainly described with reference to FIG. 13 . In addition, in FIG. 13, for the sake of convenience, the same reference numerals are given to some of the configurations that are the same as or correspond to the configurations shown in FIG. 4 and the like.

The outer diameter dimension of the cylindrical portion 31 forming the first joint portion 30 is slightly smaller than the inner diameter dimension of the lower steel pipe pile 10 . The lower end of the cylindrical portion 31 is welded to the inner peripheral surface of the upper end of the lower steel pipe pile 10 while the cylindrical portion 31 is fitted to the upper end of the lower steel pipe pile 10 from the inside. On the other hand, the upper end portion of the annular portion 41 is welded to the inner peripheral surface of the upper steel pipe pile 20 in a state where the annular portion 41 is fitted from the inside to the position retreated upward from the axial lower end of the upper steel pipe pile 20. are spliced.

The outer diameter dimension of the first joint portion 30 is slightly smaller than the inner diameter dimension of the upper steel pipe pile 20 . This allows the first joint portion 30 to be loosely fitted to the upper steel pipe pile 20 . A portion of the upper steel pipe pile 20 below the second joint portion 40 serves as a guide portion for fitting the first convex portion 32 to the second concave portion 43 . This guide portion is fitted into the cylindrical portion 31 of the first joint portion 30 , and the first projection 32 is fitted into the second recess 43 . In this state, the upper end surface 11 of the lower steel pipe pile 10 is separated from the lower end surface 21 of the upper steel pipe pile 20 .

A plurality of inner through holes 36 are formed in the cylindrical portion 31 of the first joint portion 30 so as to be arranged at regular intervals in the circumferential direction of the first joint portion 30 . At the lower end of the upper steel pipe pile 20 , outer through holes 46 are formed in the same number as the inner through holes 36 so as to be arranged at equal intervals in the circumferential direction of the upper steel pipe pile 20 . The first protrusion 32 is fitted into the second recess 43 so that one of the inner through holes 36 and one of the outer through holes 46 are aligned. Thereby, the through holes 36 and 46 that penetrate from the outer peripheral surface of the upper steel pipe pile 20 to the inner peripheral surface of the first joint portion 30 are formed. The inner peripheral surface of each through hole 36 , 46 is continuous from the outer peripheral surface of the upper steel pipe pile 20 to the inner peripheral surface of the first joint portion 30 . A sleeve 50 is fitted in each through hole 36 , 46 .

In addition, as shown in FIG. 14, the portion of the upper steel pipe pile 20 below the second joint portion 40 is fitted to the cylindrical portion 31, and the first convex portion 32 is fitted to the second concave portion 43. You may implement the process of joining the outer peripheral surface in the lower end part of the 1st joint part 30, and the upper end surface 11 of the lower steel pipe pile 10 by welding after implementation. In this case, a welded portion is provided in the gap between the upper end surface 11 of the lower steel pipe pile 10 and the lower end surface 21 of the upper steel pipe pile 20 . As a result, while preventing the welded portion from protruding from the outer peripheral surface of each of the steel pipe piles 10 and 20, as shown in FIG. , welding work can be easily performed. Incidentally, the upper end surface 11 of the lower steel pipe pile 10 may be welded to the lower end surface 21 of the upper steel pipe pile 20 in addition to the outer peripheral surface of the lower end portion of the first joint portion 30 .

DESCRIPTION OF SYMBOLS 10... Lower side steel pipe pile (1st steel pipe pile), 20... Upper side steel pipe pile (2nd steel pipe pile), 30... First joint part, 40... Second joint part, 50... Sleeve.

Claims (6)

In a steel pipe pile connection structure that connects ends of cylindrical steel pipe piles (10, 20) arranged vertically,
A first steel pipe pile (10), which is one of the vertically arranged steel pipe piles, is provided so as to be concentric with the first steel pipe pile on either inner or outer side in the radial direction of the first steel pipe pile. a cylindrical first joint portion (30);
The second steel pipe pile (20), which is the other of the vertically arranged steel pipe piles, is concentric with the second steel pipe pile on the same side as the first joint part in the radial direction inside and outside of the second steel pipe pile. A cylindrical second joint portion (40) provided to be
with
The first joint portion extends beyond the axial end face (11) of the first steel pipe pile toward the second joint portion side,
The second joint portion is provided at a position retreated in the axial direction from the axial end face (21) of the second steel pipe pile to the opposite side of the first steel pipe pile,
A convex portion (32) projecting in the axial direction toward the second joint portion is formed at an end portion of the first joint portion,
A concave portion (43) is formed at an end portion of the second joint portion, which is concave in the axial direction opposite to the first joint portion side and is fitted to the convex portion,
In a state in which the portion of the second steel pipe pile closer to the first joint portion than the second joint portion is fitted into the first joint portion, and the convex portion is fitted into the recess, the first The steel pipe pile and the second steel pipe pile are spaced apart, and the first steel pipe pile and the second steel pipe pile are concentric,
Through holes (34, 44, 45, 36, 46) are formed that penetrate the first joint portion and the second steel pipe pile in the radial direction, respectively, in a state where the convex portion is fitted in the concave portion,
In order to connect the first joint portion and the second steel pipe pile, a sleeve (50) fitted into the through hole so as to straddle the through holes of the first joint portion and the second steel pipe pile. A connection structure of steel pipe piles. The sleeve has a cross-sectional area that decreases as it goes radially inward of the steel pipe pile, and has a frustum shape whose height direction is the radial direction of the steel pipe pile,
The opening area of the through-hole becomes smaller toward the inside in the radial direction of the steel pipe pile,
The connection structure of steel pipe piles according to claim 1, wherein each conical surface of said sleeve is in close contact with the inner peripheral surface of said through hole. The axial length dimension of the through hole (45) formed in the second steel pipe pile is larger than the axial length dimension of the portion of the sleeve that is inserted into the second steel pipe pile. The connection structure of the steel pipe pile according to claim 1. 4. The sleeve according to any one of claims 1 to 3, wherein the sleeve is a laterally elongated sleeve in which the length dimension in the circumferential direction of the steel pipe pile is larger than the length dimension in the axial direction of the steel pipe pile in a cross section. connected structure of steel pipe piles. The first joint portion is provided radially inside the first steel pipe pile,
The second joint portion is provided radially inside the second steel pipe pile,
In a state where the convex portion is fitted into the recess, the first joint portion and the first steel pipe pile are placed between the end face (11) of the first steel pipe pile and the end face (21) of the second steel pipe pile. The steel pipe pile connection structure according to any one of claims 1 to 4, wherein a welded portion is provided with. A cylindrical first joint portion (30) is joined to the first end side of the cylindrical steel pipe pile (10, 20) so as to be concentric with the steel pipe pile, and on the second end side of the steel pipe pile, In the steel pipe pile manufacturing method comprising a joining step of joining a cylindrical second joint portion (40) so as to be concentric with the steel pipe pile,
A convex portion (32) is formed at the end of the first joint portion and protrudes in the axial direction from the second end side of the steel pipe pile to the first end side,
A recess (43) recessed from the second end side of the steel pipe pile to the first end side in the axial direction is formed at the end of the second joint part,
The concave dimension in the axial direction of the concave portion is the same as the projection dimension in the axial direction of the convex portion,
In the joining step, the distance (LA) in the axial direction from the end surface (11) on the first end side of the steel pipe pile to the tip of the convex portion is the above-mentioned distance (LA) from the end surface (21) on the second end side of the steel pipe pile. A step of joining the first joint portion and the second joint portion to either the inner or outer side in the radial direction of the steel pipe pile so as to be larger than the distance (LB) in the axial direction to the base end of the recess. ,
A through hole (34, 44, 45, 36, 46) is formed through each of the second end side of the steel pipe pile and the first joint portion in the radial direction and into which the sleeve (50) is fitted. has been
Of the steel pipe piles arranged vertically, the second end side of one steel pipe pile (20) is fitted to the first joint portion provided on the other steel pipe pile (10), and the one steel pipe When the concave portion of the pile is fitted to the convex portion of the other steel pipe pile, the through hole on the second end side of the one steel pipe pile and the first joint portion provided on the other steel pipe pile A method for manufacturing a steel pipe pile, wherein the through hole of the steel pipe pile is coaxial.

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