TWI602971B - Joint structure for steel pipe pile - Google Patents

Description

Joint structure of steel pipe pile

FIELD OF THE INVENTION The present invention relates to a joint structure for a steel pipe pile. This case is based on Japanese Patent Application No. 2015-231400 filed on November 27, 2015 in Japan, and claims priority.

BACKGROUND OF THE INVENTION Conventionally, in order to achieve a narrow construction or a short construction period, a mechanical joint without fusion is required. For example, in order to connect a plurality of steel pipe piles in the axial direction with a mechanical joint, a joint structure of steel pipe piles disclosed in Patent Documents 1 and 2 has been proposed.

In the joint structure of the steel pipe pile disclosed in Patent Document 1, the first pile and the second pile which are adjacent to each other in the axial direction are formed to be mutually fitted with one of the outer fitting end portions and the inner fitting end portion. In the joint structure, the engaging portion and the engaged portion are formed, and the engaging portion and the engaged portion are in a state in which the fitting end portion is fitted to the fitting end portion, and the relative rotation about the shaft core is performed. And they get stuck with each other. In the joint structure of the steel pipe pile shown in Patent Document 1, the engaging portion and the engaged portion are provided to prevent the engaged portion and the engaged portion from being separated from each other in the radial direction of the first pile or the second pile. Block the means of separation.

In the joint structure of the steel pipe pile disclosed in Patent Document 2, the first pile and the second pile which are adjacent to each other in the axial direction are respectively formed with one of the outer fitting end portions and the inner fitting end portion. In the joint structure, a plurality of engaging convex portions and engaged convex portions are formed in the axial direction, and the engaging convex portions and the engaged convex portions are fitted to the fitting end portions and the fitting end portions. In the state, they are engaged with each other by relative rotation about the axis. In the joint structure of the steel pipe pile disclosed in Patent Document 2, the outer fitting end portion is formed at a position where the engaging convex portion provided on the distal end portion side is formed so that the engaging convex portion having the diameter provided on the proximal end portion side is large. . Further, the fitting end portion is formed at the position where the engaged convex portion is provided on the distal end portion side, and is formed to have a smaller diameter than the portion where the engaged convex portion is provided on the proximal end portion side. Advanced technical literature

[Patent Document 1] Japanese Laid-Open Patent Publication No. H11-43937

SUMMARY OF THE INVENTION PROBLEMS TO BE SOLVED BY THE INVENTION In the joint structure of a steel pipe pile, a plurality of steel pipe piles are connected to each other in a direction of a core direction, and a force of compression, stretching, and bending acts on the joint portion. The joint structure of the steel pipe pile disclosed in Patent Document 1 is from the base end side to the front end side of the outer end portion and the inner end portion, and the load ratio of the force of compression and stretching and bending is different, but the engagement portion is The plate thickness is all the same in the direction of the core. Therefore, in the joint structure of the steel pipe pile disclosed in Patent Document 1, in particular, the portion of the thickness of the front end portion of the outer end portion and the inner end portion is excessively increased, and the thickness of the plate is increased excessively, resulting in an increase in cost. .

On the other hand, in the joint structure of the steel pipe pile disclosed in Patent Document 2, the thickness of the engaged convex portion is gradually reduced by the base end side of the outer end portion and the inner end portion toward the front end side, and compression is considered. The burden rate with the force of stretching and bending. However, in the joint structure of the steel pipe pile shown in Patent Document 2, since the thickness of the engaged convex portion is the same at the outer end portion and the inner end portion, the weight of the steel material having the entire joint is excessively increased, resulting in cost. The problem of rising.

Further, the joint structure of the steel pipe pile disclosed in Patent Document 2 is such that the thickness of the engaged convex portion gradually decreases from the base end side toward the front end side of the outer fitting end portion and the fitting end portion, whereby the core core is gradually smaller. It is formed in a tapered shape in the direction. However, in the joint structure of the steel pipe pile disclosed in Patent Document 2, the ratio of the protruding height of the compression surface to the protruding height of the stretched surface is less than 0.50. Therefore, it is impossible to minimize the weight of the steel for ensuring the compression and the allowable stress of the tensile and bending, and the problem of the material cost is increased.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a joint structure of a steel pipe pile which is improved in workability by reducing weight. Means of solving problems

(1) A joint structure of a steel pipe pile according to an aspect of the present invention is a first steel pipe pile having an outer end portion and a second steel pipe pile having an inner end portion at the outer fitting end portion and the inner fitting end portion The connector in the same state of the same core wire is characterized in that, when the cross section is viewed along the axial line, the plurality of positions along the axial line of the inner side of the outer end portion are oriented toward the second steel pipe pile stage. The outer block portion is provided in a manner of expanding the diameter, and each of the outer block portions has a mountain portion that is relatively close to the second steel pipe pile and an outer valley portion that is adjacent to the outer mountain portion. The inner block portion is provided at a plurality of positions on the outer side of the inner end portion along the axial line, and the inner block portion is provided to be gradually reduced in diameter toward the first steel pipe pile, and each of the inner block portions has a relatively close proximity to the first portion An inner mountain portion of the steel pipe pile and an inner valley portion adjacent to the inner mountain portion, each of the inner mountain portions being rotated relative to the axial core wire by inserting the inner end portion into the outer fitting end portion In the state, it is locked in each of the aforementioned externally embedded mountains, each In the outer mountain portion, the protruding height of the outer mountain portion of the second steel pipe pile is relatively close to the outer height of the outer mountain portion, and the ratio of the protruding height of the outer mountain portion located beside the outer mountain portion is 0.5 or more and 0.9. Hereinafter, in each of the inlaid mountain portions, the protruding height of the inlaid mountain portion of the first steel pipe pile is relatively close to each other, and the ratio of the protruding height of the inlaid mountain portion located beside the inlaid mountain portion is 0.5. Above 0.9 or less, the thickness of the outer trough portion closest to the second steel pipe pile is smaller than the thickness of the inner trough portion closest to the first steel pipe pile, and is closest to the first steel pipe pile. The thickness of the inlaid valley portion is set to be 0.84 or more in addition to the thickness of the outer trough portion of the second steel pipe pile.

According to the joint structure of the steel pipe pile composed of the above configuration, the joint weight of the steel pipe pile can be reduced, and the workability can be improved.

(2) In the joint structure of the steel pipe pile according to the above (1), the plate having the outermost valley portion closest to the first steel pipe pile is selected to be the closest to the outer grain portion of the second steel pipe pile. The thickness ratio is 0.84 or more and 0.94 or less.

In this case, the weight of the joint of the steel pipe pile can be further reduced.

(3) The joint structure of the steel pipe pile according to the above (1) or (2), wherein each of the outer mountain portions is relatively close to the protruding height of the outer mountain portion of the second steel pipe pile, except for The ratio of the protruding height of the externally-embedded mountain portion beside the outer mountain portion is 0.6 or more and 0.8 or less, and each of the inlaid mountain portions is relatively close to the protruding height of the inlaid mountain portion of the first steel pipe pile. The ratio of the protruding height of the embedded mountain portion located beside the embedded mountain portion is 0.6 or more and 0.8 or less.

In this case, the strength of the steel pipe pile as a joint can be maintained, and the weight of the joint of the steel pipe pile can also be reduced. Effect of the invention

According to the joint structure of the steel pipe pile according to the above aspect of the invention, the workability is improved by reducing the joint weight.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to the embodiments.

<First Embodiment> The joint structure 7 of the steel pipe pile according to the present embodiment is used for a landslide pile, a support pile, a friction pile, etc., and as shown in Fig. 1, the first steel pipe pile 1 and the second one having a slightly circular cross section are used. The steel pipe pile 2 is connected to the core direction Y.

The joint structure 7 of the steel pipe pile has an outer fitting end portion 3 and an inner fitting end portion 5 which are freely fitted to each other. The outer end portion 3 is attached to the end portion of the first steel pipe pile 1 by welding or the like, and the inner end portion 5 is attached to the end portion of the second steel pipe pile 2 by welding or the like. In a state where the outer end portion 3 and the inner end portion 5 share the same axial core line L, the outer fitting end portion 3 and the inner fitting end portion 5 oppose each other in the axial direction Y parallel to the axial line L. a pair.

The joint structure 7 of the steel pipe pile is mainly such that the outer groove portion 32 is formed inside the outer end portion 3, and the inner groove portion 52 is formed outside the inner end portion 5. The joint structure 7 of the steel pipe pile is applied to a gear type joint in which a plurality of externally embedded mountain portions 31 and a plurality of inlaid mountain portions 51 are formed on a slightly circumferential circumference in the circumferential direction W. Here, each of the first steel pipe pile 1 and the second steel pipe pile 2 is such that the outer diameter Dp of the steel pipe pile is about 318.5 mm to 1625.6 mm, and the thickness t of the steel pipe pile is about 6.0 mm to 30.0 mm. Object.

The outer fitting end portion 3 has a plurality of outer fitting mountain portions 31 which are formed to protrude inward in the direction X orthogonal to the axial core, and a plurality of outer fitting groove portions 32 which are formed adjacent to the outer embedded mountain portion 31 in the circumferential direction W. And in the axial direction Y, the valley portion 33 is formed closer to the proximal end side B than the outer embedded portion 31. The outer fitting end portion 3 is formed by the outer fitting mountain portion 31 and the outer fitting valley portion 33 being alternately adjacent in the axial direction Y.

The outer fitting end portion 3 is formed alternately in the circumferential direction W between the outer inlaid mountain portion 31 and the outer fitting groove portion 32, and the plurality of outer inlaid mountain portions 31 are arranged in a row in the axial direction Y and the circumferential direction W, and The plurality of outer fitting groove portions 32 are arranged in a line in the axial direction Y and the circumferential direction W. The outer fitting end portion 3 has an outer fitting length portion 38 at a portion attached to the end portion of the first steel pipe pile 1 by welding or the like.

The inlaid end portion 5 has a plurality of inlaid mountain portions 51 formed to protrude outward in a direction X orthogonal to the axis, and a plurality of inlaid portions formed adjacent to the inlaid mountain portion 51 in the circumferential direction W The groove portion 52; and the inner valley portion 53 formed in the axial direction Y closer to the proximal end side B than the inner embedded portion 51. The inlaid end portion 5 is formed by the inlaid mountain portion 51 and the inlaid valley portion 53 being alternately adjacent in the axial direction Y.

The inlaid end portion 5 is formed by the inlaid mountain portion 51 and the inlaid groove portion 52 being alternately formed in the circumferential direction W, and the plurality of inlaid mountain portions 51 are arranged in a row in the axial direction Y and the circumferential direction W, and The plurality of in-line grooves 52 are arranged in a line in the axial direction Y and the circumferential direction W. The fitting end portion 5 has an inlaid excess length portion 58 as a portion attached to the end portion of the second steel pipe pile 2 by welding or the like.

As shown in FIG. 2, the outer mountain portion 31 has a groove portion 32 adjacent to the circumferential direction W and a valley portion 33 adjacent to the axial direction Y, and further to the axial direction of the first steel pipe pile 1. The central axis of Y is formed to be slightly rectangular. At this time, the outer mountain portion 31 is as shown in FIG. 3, and the valley portion 33 is protruded in the direction X orthogonal to the axis core from the side adjacent to the front end side A or the base end side B in the axial direction Y. It is formed by protruding heights Hc and Ht.

The outer valley portion 33 is provided with a plurality of outer block portions 4 from the front end side A to the base end side B in the axial direction Y, and each of the outer block portions 4 is formed to have a direction X orthogonal to the shaft core. The thickness of the board is predetermined. The outer valley portion 33 is formed such that the block portion 4 is adjacent to the outer peripheral portion 38 in the axial direction Y except that the axial direction Y is the most proximal end side B, and the outer peripheral length portion 38 is The direction X orthogonal to the core has a predetermined plate thickness D.

In particular, the block portion 4 becomes the first outer block portion 41 except that the core direction Y is the foremost end side A. When the outer block portion 4 is provided in four stages in the axial direction Y, for example, the outer block portion 33 has the first outer block in this order from the front end side A to the base end side B in the axial direction Y. The portion 41, the second outer block portion 42, the third outer block portion 43, and the fourth outer block portion 44.

In other words, when the outer end portion 3 is viewed in a cross section including the axial line L, the plurality of positions along the axial line L inside the outer end portion 3 are expanded in a stepwise manner toward the second steel pipe pile 2 The outer block portion 4 is provided in a manner. Each of the outer block portions 4 has a mountain portion 31 that is adjacent to the second steel pipe pile 2 and a valley portion 33 that is adjacent to the outer mountain portion 31. Further, from the cross-sectional views of FIGS. 3, 5, 8, 13 and 16, the hatching is omitted for easy viewing.

As shown in FIG. 4, the inlaid mountain portion 51 has an inner groove portion 52 adjacent to the circumferential direction W and an inner valley portion 53 adjacent to the axial direction Y toward the axis of the second steel pipe pile 2. The side opposite to the central axis of the direction Y protrudes to form a substantially rectangular shape or the like. At this time, as shown in FIG. 5, the inlaid mountain portion 51 is embedded in the valley portion 53 adjacent to the front end side A or the base end side B in the axial direction Y, and is projected in the direction X orthogonal to the shaft core. The protruding heights Hc and Ht are formed.

The inner valley portion 53 is provided with a plurality of inner block portions 6 from the front end side A to the base end side B in the axial direction Y, and each of the inner block portions 6 is formed to have a predetermined direction X in a direction orthogonal to the shaft core. Plate thickness. The inlaid valley portion 53 is formed such that the inner block portion 6 is adjacent to the inlaid excess length portion 58 in the axial direction Y in the axial direction Y as the most proximal end side B, and the inlaid excess length portion 58 is in the axis The direction X of the core is orthogonal to a predetermined thickness D. Furthermore, the thickness D of the inlaid excess length portion 58 does not have to coincide with the thickness D of the outer peripheral portion 38.

The inner block portion 53 is the first inner block portion 61 particularly in the innermost end side A in the axial direction Y. The inlaid valley portion 53 is, for example, provided with the inner block portion 6 in four stages in the axial direction Y, and has the first inner block in the axial direction Y from the front end side A to the base end side B. The portion 61, the second inner block portion 62, the third inner block portion 63, and the fourth inner block portion 64.

That is, when the in-line end portion 5 is viewed in cross section along the axis line L, a plurality of positions along the axis line L on the outer side of the inlaid end portion 5 are stepwise toward the first steel pipe pile 1 The inner block portion 6 is provided in a reduced diameter manner. Each of the inner block portions 6 has an inner mountain portion 51 that is relatively close to the first steel pipe pile 1 and an inner valley portion 53 that is adjacent to the inner mountain portion 51.

As shown in FIGS. 6 and 7, the joint structure 7 of the steel pipe pile is fitted to each other by the outer end portion 3 and the inner end portion 5, and the first steel pipe pile 1 and the second steel pipe pile 2 are coupled to each other in the axial direction Y.

The joint structure 7 of the steel pipe pile is initially inserted into the outer end portion 3 of the first steel pipe pile 1 by inserting the inner end portion 5 attached to the second steel pipe pile 2 as shown in Fig. 6 . At this time, the joint structure 7 of the steel pipe pile is equal to or less than the depth of the direction in which the inlaid groove portion 52 and the outer groove portion 32 are orthogonal to the axis core by the protruding height of the outer mountain portion 31 and the inlaid mountain portion 51, and is embedded. The mountain portion 31 and the inlaid mountain portion 51 can pass through the groove portion 52 and the outer frame portion 32.

Next, as shown in FIG. 7, the joint structure 7 of the steel pipe pile is such that the first steel pipe pile 1 and the second steel pipe pile 2 are wound around the axial core line L while the inner end portion 5 is inserted into the outer fitting end portion 3. The circumferential direction W is relatively rotated. At this time, the joint structure 7 of the steel pipe pile is equal to or less than the depth of the direction in which the inlaid valley portion 53 and the outer valley portion 33 are orthogonal to the axis X by the protruding height of the outer mountain portion 31 and the inlaid mountain portion 51. The inlaid mountain portion 31 and the inlaid mountain portion 51 can be embedded in the inlaid valley portion 53 and the outer inlaid valley portion 33.

The joint structure 7 of the steel pipe pile is set such that the length of the axial direction Y of the outer mountain portion 31 is equal to or less than the length of the axial direction Y of the embedded valley portion 53, and the length of the axial direction Y of the embedded mountain portion 51 is It is set to be equal to or less than the length of the core direction Y of the outer valley portion 33. At this time, the joint structure 7 of the steel pipe pile is in a state where the inner end portion 5 inserted into the outer fitting end portion 3 is relatively rotated in the circumferential direction W, and the outer mountain portion 31 and the inner mountain portion 51 are in the axial core. The directions Y are locked to each other. Further, in the case of the outer end portion 3 or the inner end portion 5, the number of the embedded portion 31 or the inlaid mountain portion 51 outside the circumferential direction W is preferably 4, 16, 32 or the like.

As shown in FIG. 8, the joint structure 7 of the steel pipe pile is such that the tensile force Pt acts on the first steel pipe pile 1 and the second steel pipe pile 2 in a state in which the outer mountain portion 31 and the inner mountain portion 51 are locked to each other. The direction in which the core direction Y is spaced apart from each other. At this time, the outer mountain portion 31 is a stretching surface 31a which is the base end side B of the axial direction Y, and the tensile force Pt is transmitted from the inner mountain portion 51. At the same time, the inlaid mountain portion 51 borrows the stretching surface 51a which is the base end side B of the axial direction Y, and transmits the tensile force Pt from the stretching surface 31a of the outer molding portion 31.

The joint structure 7 of the steel pipe pile is such that the stretched surface 31a of the outer mountain portion 31 and the stretched surface 51a of the embedded mountain portion 51 have a predetermined protruding height Ht in the direction X orthogonal to the axial center. Further, the stretched surface 31a of the embedded mountain portion 31 and the stretched surface 51a of the embedded mountain portion 51 convey the tensile force Pt of the same magnitude. At this time, the tensile force Pt of each of the outer block portion 4 and the inner block portion 6 is transmitted from the front end side A toward the base end side B in the axial direction Y to the respective outer cavities 31 and the inlaid mountain portions 51. The burden rate is gradually increasing. As a result, the tensile force pt of the fourth outer block portion 44 and the fourth inner block portion 64 which are the most proximal side B is the highest.

Further, as shown in FIG. 9, the joint structure 7 of the steel pipe pile is such that the compressive force Pc acts on the first steel pipe pile 1 and the second steel pipe pile 2 in a state in which the outer mountain portion 31 and the inner mountain portion 51 are locked to each other. A direction approaching each other in the axial direction Y. At this time, the outer casing portion 31 is the compression surface 31b which is the front end side A of the axial direction Y, and the compression force Pc is transmitted from the inner mountain portion 51. At the same time, the inlaid mountain portion 51 is the compression surface 51b which is the front end side A of the axial direction Y, and the compression force Pc is transmitted from the compression surface 31b of the outer mountain portion 31.

The joint structure 7 of the steel pipe pile is such that the compression surface 31b of the outer mountain portion 31 and the compression surface 51b of the inner mountain portion 51 have a predetermined protruding height Hc in the direction X orthogonal to the axial center. Further, the compression surface Pb of the same size is transmitted by the compression surface 31b of the embedded mountain portion 31 and the compression surface 51b of the embedded mountain portion 51. At this time, the compression force Pc of each of the outer block portion 4 and the inner block portion 6 is transmitted from the front end side A to the base end side B in the axial direction Y to the respective outer cavities 31 and the inlaid mountain portions 51. The burden rate is gradually increasing. As a result, the load factor of the compressive force Pc of the fourth outer block portion 44 and the fourth inner block portion 64 which becomes the most proximal end side B is the largest.

In the joint structure 7 of the steel pipe pile according to the present embodiment, as shown in Fig. 10, the outer valley portion 33 and the inner valley portion 53 are formed in the outer block portion 4 and the inner block portion 6 so as to be orthogonal to the shaft core. There is a predetermined plate thickness in the direction X.

In the outer valley portion 33, the valley portion 33 has a thickness tb1 outside the first outer block portion 41, and the valley portion 33 has a thickness tb2 outside the second outer block portion 42, and the third outer layer is embedded. The valley portion 33 outside the segment portion 43 has a plate thickness tb3, and the valley portion 33 outside the fourth outer block portion 44 has a plate thickness tb4. The outer valley portion 33 is particularly the outer block portion 4 adjacent to the axial direction Y, and the thickness of the outer valley portion 33 of the block portion 4 outside the base end side B in the axial direction Y is larger than that in the axial core The outer thickness portion 33 of the outer block portion 4 in the direction Y upper end side A has a large plate thickness.

At this time, when the outer block portion 33 is provided with the outer block portion 4 in four stages from the front end side A to the base end side B in the axial direction Y, the thickness tb2 of the second outer block portion 42 is higher than that of the first The outer block portion 41 has a large thickness tb1. Further, the outer valley portion 33 is gradually larger than the thickness tb2 of the second outer block portion 42 in the thickness tb3 of the third outer block portion 43, and is thicker than the thickness tb4 of the fourth outer block portion 44. It is larger than the thickness tb3 of the third outer block portion 43.

The inlaid valley portion 53 has a thickness tp1 in the inner valley portion 61 and a thickness tp2 in the inner inner block portion 62, and the third inner inlay is formed in the third inner block portion 62. The inner valley portion 53 of the segment portion 63 has a plate thickness tp3, and the inner valley portion 53 of the fourth inner block portion 64 has a plate thickness tp4. The inner valley portion 53 is particularly an inner block portion 6 adjacent to the axial direction Y, and the thickness of the inner valley portion 53 of the inner block portion 6 at the proximal end side B in the axial direction Y is larger than that in the axial core. The thickness of the inner valley portion 53 of the inner block portion 6 in the direction Y upper end side A is large.

At this time, when the inner valley portion 53 is provided with the inner block portion 6 in four stages from the front end side A to the base end side B in the axial direction Y, the thickness tp2 of the second inner block portion 62 becomes higher than that in the second inner block portion 62. The thickness tp1 of the first inner block portion 61 is large. Further, the inlaid valley portion 53 has a thickness tp3 larger than the thickness tp2 of the second inner block portion 62 and a thickness tp4 at the fourth inner block portion 64. It becomes larger than the plate thickness tp3 of the third inner block portion 63.

In the joint structure 7 of the steel pipe pile, in the state in which the outer end portion 3 and the inner end portion 5 are relatively rotated, the outer block portion 4 and the inner block portion 6 are disposed at positions corresponding to each other in the axial direction Y. . The outer valley portion 33 and the inner valley portion 53 are disposed at the outer block portion 4 and the inner block portion 6 at positions corresponding to each other, and the outer mountain portion 31 and the inner mountain portion 51 are locked to each other in the axial direction Y. .

At this time, the outer valley portion 33 and the inner valley portion 53 are the first outer block portion 41 and the inner side portion 31 and the inner inner block portion 64 of the fourth inner block portion 64 are locked, and the second outer portion is locked. The embedded portion 31 of the block portion 42 and the inlaid mountain portion 51 of the third inner block portion 63 are locked. Further, the outer valley portion 33 and the inner valley portion 53 are such that the outer portion of the third outer block portion 43 and the inner portion 51 of the second inner block portion 62 are locked, and the fourth outer portion is embedded. The embedded portion 31 of the segment portion 44 and the inlaid mountain portion 51 of the first inner block portion 61 are locked.

In the joint structure 7 of the steel pipe pile, in particular, the thickness tb1 of the valley portion 33 other than the first outer block portion 41 is smaller than the thickness tp1 of the inner valley portion 53 in the first inner block portion 61. Further, the thickness tb2 of the valley portion 33 outside the second outer block portion 42 is smaller than the thickness tp2 of the inner valley portion 53 in the second inner block portion 62. Further, the thickness tb3 of the valley portion 33 outside the third outer block portion 43 is smaller than the thickness tp3 of the valley portion 53 in the third inner block portion 63. Further, the thickness tb4 of the valley portion 33 outside the fourth outer block portion 44 is smaller than the thickness tp4 of the valley portion 53 in the fourth inner block portion 64.

Further, the joint structure 7 of the steel pipe pile is characterized in that the difference Δb between the thicknesses of the valley portions 33 other than the outer block portion 4 adjacent to the axial direction Y and the adjacent portions in the axial direction Y are The difference Δp in the thickness of the inner valley portion 53 of the block portion 6 is such that Δb1 = (tb2 - tb1) and Δp3 = (tp4 - tp3) are slightly the same, and Δb2 = (tb3 - tb2) and Δp2 = (tp3-tp2) is slightly the same, so that Δb3=(tb4-tb3) and Δp1=(tp2-tp1) are slightly the same, whereby they can be fitted to each other. Therefore, the joint structure 7 of the steel pipe pile has the following characteristics: by determining the plate thickness tp1 and the plate thickness ratio (tb1/tp1) of the ratio of the plate thickness tb1 to the plate thickness tp1, tb1, tb2, tb3, tb4, tp1 can be derived. Tp2, tp3, and tp4 are all.

For example, the joint structure 9 of the conventional steel pipe pile shown in Patent Document 2 is as shown in Fig. 11, the plate thickness tb1 is the same as the plate thickness tp1, the plate thickness tb2 is the same as the plate thickness tp2, and the plate thickness tb3 is the same as the plate thickness tp3. The thickness of the plate tb4 is the same as the thickness tp4. Therefore, when the first inner block portion 61 is compared with the first outer block portion 41, the cross-sectional area of the first inner block portion 61 which is present inside in the radial direction is smaller than that of the first inner block portion 61. small. Further, similarly, in the second inner block portion 62, the third inner block portion 63, and the fourth inner block portion 64, the cross-sectional area of the inner block portion 6 is smaller than the cross-sectional area of the outer block portion 4. Thereby, the cross-sectional area of the fitting end portion 5 becomes smaller than the outer fitting end portion 3. Therefore, the conventional joint structure 9 of the steel pipe pile determines the allowable stress of the inner end portion 5 and the outer end portion 3 based on the failure of the inner end portion 5 having a small cross-sectional area, and has an outer end portion. 3 becomes a disadvantage of redundant design.

Further, when the tensile force acts, the outer fitting end portion 3 is generally extended toward the outer side in the direction X orthogonal to the axial direction, on the side opposite to the central axis of the axial direction Y of the first steel pipe pile 1. Deformation. On the other hand, the fitting end portion 5 is generally deformed so as to be retracted inward in the direction X orthogonal to the axis of the core toward the central axis of the axial direction Y of the second steel pipe pile 2. Therefore, in consideration of the expansion of the stress in the circumferential direction when the tensile force acts, the inner end portion 5 is deformed so as to be retracted toward the inner side, and the stress is hard to spread to the circumferential direction. On the other hand, the outer fitting end portion 3 is deformed so as to expand outward, and the stress easily spreads to the circumferential direction, and the stress concentration at the outer fitting end portion 3 can be alleviated. Therefore, the joint structure 9 of the conventional steel pipe pile has the disadvantage that the outer end portion 3 becomes a redundant design from the viewpoint of the expansion of the stress in the circumferential direction and the relaxation of the stress concentration in addition to the above-described cross-sectional area. .

On the other hand, in the joint structure 7 of the steel pipe pile according to the present embodiment, as shown in FIG. 10, the thickness tb1 of the valley portion 33 outside the first outer block portion 41 is set to be larger than the first inner block. The thickness tp1 of the valley portion 53 in the portion 61 is small, and the thickness ratio (tb1/tp1) of the ratio of the thickness tb1 to the thickness tp1 is set to 0.84 or more. In other words, in the joint structure 7 of the steel pipe pile according to the present embodiment, the thickness of the valley portion 33 closest to the second steel pipe pile 2 is smaller than the thickness of the inner valley portion 53 closest to the first steel pipe pile 1, and The ratio of the thickness of the inner valley portion 53 closest to the first steel pipe pile 1 to the thickness of the valley portion 33 closest to the second steel pipe pile 2 is 0.84 or more.

Further, in the joint structure 7 of the steel pipe pile, Δb1=(tb2-tb1) and Δp3=(tp4-tp3) are set to be slightly the same, and Δb2=(tb3tb2) and Δp2=(tp3-tp2) are set to be slightly the same. The magnitude of the plate thickness tp1 is determined by setting Δb3=(tb4-tb3) and Δp1=(tp2-tp1) to be slightly the same. Further, the thickness of the valley portion 33 which is closest to the second steel pipe pile 2 is smaller than the thickness of the inner valley portion 53 which is closest to the first steel pipe pile 1, and is closest to the inner wall of the first steel pipe pile 1. The ratio of the thickness of the portion 53 to the thickness of the valley portion 33 other than the second steel pipe pile 2 is 0.84 or more. Thereby, the cross-sectional area of the outer end portion 3 can be designed based on the destruction of the inner end portion 5 having a small cross-sectional area. Thereby, the joint structure 7 of the steel pipe pile can be matched with the inner end portion 5 having a small cross-sectional area to make the cross-sectional area of the outer end portion 3 small. Thereby, the redundant design of the outer end portion 3 can be avoided, and the thickness of the outer end portion 3 can be reduced as compared with the conventional joint structure 9 of the steel pipe pile.

Further, as shown in FIG. 12, the shape of the outer peripheral length portion 38 and the inner peripheral length portion 58 may be deformed. By making such a shape, the weight reduction of the joint structure 7 of the steel pipe pile can be achieved. Here, as shown in FIG. 13(a), in the joint structure 7 of the steel pipe pile according to the present embodiment, the thickness of the valley portion 33 closest to the second steel pipe pile 2 is smaller than the closest to the first steel pipe pile 1. The thickness of the valley portion 53. On the other hand, in the conventional joint structure 9 of the steel pipe pile shown in FIG. 13(b), the thickness of the inner valley portion 53 closest to the first steel pipe pile 1 and the closest to the second steel pipe pile 2 are The outer valley portion 33 has the same plate thickness. Fig. 13 (c) is a comparison diagram showing Fig. 13 (a) and Fig. 13 (b). In Fig. 13(c), the conventional joint structure 9 of the steel pipe pile of Fig. 13(b) is indicated by a broken line. Accordingly, it is understood that the joint structure 7 of the steel pipe pile of the present embodiment particularly reduces the thickness of the entire outer end portion 3.

Here, FIG. 14 is a numerical analysis and experimental results showing the allowable stress of the joint of the steel pipe pile to be joined in the joint structure of the steel pipe pile according to the present embodiment. The shape ratio of this embodiment is applied and designed to give a design safety rate. Furthermore, in order to obtain the allowable stress of the joint, in the numerical analysis, the steel pipe pile is calculated as a completely elastic material. Further, in the experiment, a steel pipe having a higher strength than the steel pipe corresponding to the original joint was used to break the joint first. The range of the steel pipe pile to which the joint is applied is such that the outer diameter Dp is set to 400.0 mm to 1600.0 mm, and the thickness tp of the steel pipe pile is set to 6.0 mm to 30.0 mm. The material specifications are SM570 as defined in JSK A and JIS G 3106 as defined in JIS A 5525. Fig. 14 is a graph showing the maximum bending of the joint structure 7 of the steel pipe pile of the present embodiment calculated by FEM analysis, with the aspect ratio (Dp/tp) of the outer diameter Dp of the joined steel pipe pile and the thickness tp as the horizontal axis. The ratio (Mmax/Mp) of the moment Mmax (joint portion) to the full plastic bending moment Mp (steel tube portion) of the steel pipe pile is the vertical axis. As can be seen from Fig. 14, even if the thickness tb of the outer fitting end portion 3 is reduced, the maximum bending moment Mmax of the joint exceeds the total plastic bending moment Mp of the joined steel pipe. Moreover, since the joint is stronger than the steel pipe, it is understood that the joint is not damaged before the steel pipe. Table 1 shows the numerical data of Figure 14.

【Table 1】

15A and 15B show a basis in which the thickness of the outer valley portion 33 and the inner valley portion 53 are different. In Fig. 15A, the ratio of the diameter to the thickness (Dp/tp1) of the outer diameter Dp of the steel pipe pile and the thickness tp1 of the valley portion 53 in the first inner block portion 61 is the horizontal axis. Further, in Fig. 15A, the maximum bending moment Mmax of the joint structure 7 of the steel pipe pile according to the present embodiment calculated by FEM analysis and the full plasticity of the inlaid valley portion 53 (in the case where the entire valley portion of the joint is effective) are fully plasticized. The allowable stress ratio (Mmax/Mf) of the bending moment Mf is the vertical axis. In Fig. 15B, the ratio of the diameter to thickness (Dp/tb1) of the outer diameter Dp of the steel pipe pile and the thickness tb1 of the valley portion 33 outside the first outer block portion 41 is the horizontal axis. In Fig. 15B, the allowable stress ratio (Mmax/Mf) of the maximum bending moment Mmax of the present invention calculated by FEM analysis and the total plastic bending moment Mf of the outer valley portion 33 is the vertical axis. According to FIG. 15A, it is understood that the allowable stress ratio also changes when the ratio of the thickness to the thickness of the inlaid end portion 5 is changed. Therefore, the allowable stress ratio is a linear function of the ratio of the diameter to the thickness. On the other hand, according to FIG. 15B, it is understood that the allowable stress ratio is constant in the outer valley portion 33 without being affected by the ratio of the diameter to the thickness. In addition, in FIGS. 15A and 15B, the outer diameter Dp of the steel pipe pile is 400.0 mm to 1600.0 mm, and the thickness t of the steel pipe pile is 6.0 mm to 30.0 mm, and the normal material specifications of the steel pipe pile are displayed. The lower limit is the SKK400 specified in JIS A 5525, and the upper limit of the material specification is shown as SM570 specified in JIS G 3106. Table 2 shows the numerical data of Figs. 15A and 15B. 【Table 2】

Here, the outer end portion 3 and the inner end portion 5 of the joint structure 7 of the steel pipe pile are formed to have a substantially circular cross section. Therefore, the cross-sectional area of the outer trough portion 33 is π × rb1 ² calculated from the outer diameter rb1 of the outer trough portion 33 in each outer block portion 4, minus the inner diameter rb2 of the outer trough portion 33 The calculated π × rb2 ² is (π × rb1 ^{2 -} π × rb2 ² ). Moreover, since the inner diameter rb2 of the outer trough 33 is the outer diameter rb1 of the outer trough 33 minus the thickness tb, the cross-sectional area of the outer trough 33 is twice the thickness tb of the outer trough 33. The proportional relationship. Further, the cross-sectional area of the inlaid valley portion 53 is also the same as the cross-sectional area of the outer trough portion 33, and the inner block portion 6 has a proportional relationship of twice the thickness tp of the inlaid valley portion 53.

The joint structure 7 of the steel pipe pile is as shown in Fig. 15A, and in the inner end portion 5, the ratio of the bending moment is reduced from 0.70 to 0.50 in the range of the diameter-thickness ratio of 10.00 to 200.00, so that the entire circumference of the valley portion 53 is embedded. 70 to 50% of the effective cross section. On the other hand, in the outer fitting end portion 3, as shown in Fig. 15B, the bending moment is constant irrespective of the diameter-thickness ratio, and 70% of the entire circumference of the outer valley portion 33 is an effective cross section. Therefore, when the diameter-thickness ratio is 200.00, the cross-sectional area of the outer valley portion 33 can be reduced to 71% (0.50/0.70 ≒ 0.71) when the design is based on the destruction of the inner valley portion 53. Therefore, the cross-sectional area of the outer valley portion 33 is a proportional relationship of twice the thickness tb of the outer valley portion 33, so that even if the thickness tb of the outer valley portion 33 is lowered to the thickness tp of the inner valley portion 53 0.84 times (0.84 ² ≒ 0.71), the cross-sectional area equal to or greater than the embedded valley portion 53 can be ensured. Therefore, the same allowable stress can be ensured in the outer valley portion 33 and the inner valley portion 53. When the diameter-thickness ratio is about 50, the cross-sectional area of the outer valley portion 33 can be reduced to 97% (0.68/0.70 ≒ 0.97) when the design is based on the destruction of the inner valley portion 53. Therefore, the cross-sectional area of the outer valley portion 33 is a proportional relationship of twice the thickness tb of the outer valley portion 33, even if the thickness tb of the outer valley portion 33 is lowered to 0.94 of the thickness tp of the inner valley portion 53. Double (0.97 ² ≒ 0.94), it can still ensure the same cross-sectional area as the embedded valley 53.

As described above, in the joint structure 7 of the steel pipe pile according to the present embodiment, in each of the outer block portion 4 and the inner block portion 6, the thickness tb of the outer valley portion 33 is smaller than the thickness tp of the inner valley portion 53. In the joint structure 7 of the steel pipe pile according to the present embodiment, the thickness of the valley portion 33 closest to the second steel pipe pile 2 is smaller than the thickness of the inner valley portion 53 closest to the first steel pipe pile 1, and The plate thickness of the inner valley portion 53 closest to the first steel pipe pile 1 is 0.84 or more in addition to the thickness of the valley portion 33 which is closest to the second steel pipe pile 2. Thereby, the joint structure 7 of the steel pipe pile is smaller than the joint structure 9 of the conventional steel pipe pile, and the cross-sectional area of the outer end portion 3 is reduced to avoid unnecessary design. Thereby, the maximum allowable stress of compression, stretching and bending is obtained with a small amount of steel and the like. As a result, the weight and volume of the entire joint are reduced, the efficiency of the joining operation is improved, and the increase in the material cost of the entire joint can be suppressed.

Further, as shown in Figs. 8 and 9, the joint structure 7 of the steel pipe pile according to the present embodiment is adjacent to the outer block portion 4 in the axial direction Y, and is embedded in the block portion 4 outside the base end side B. The thickness of the valley portion 33 is larger than the thickness of the valley portion 33 outside the block portion 4 outside the front end side A. Further, in the inner block portion 6 adjacent in the axial direction Y, the thickness of the inner valley portion 53 of the inner block portion 6 at the proximal end side B is smaller than the inner block portion 6 of the front end side A. The valley portion 53 has a large thickness. Further, the protruding height Hc of the compression surface 31b of the outer mountain portion 31 and the compression surface 51b of the embedded mountain portion 51 is higher than the protruding surface 31a of the outer mountain portion 31 and the protruding surface 51a of the embedded mountain portion 51. Ht is big. Further, in the first outer block portion 41 and the first inner block portion 61, the protruding height Hc of the compression surface 31b of the outer mountain portion 31 and the compression surface 51b of the inner mountain portion 51 is higher than the second outer block portion 42. The fourth outer block portion 44 and the second inner block portion 62 to the fourth inner block portion 64 are large. Thereby, each of the outer fitting end portion 3 and the inner fitting end portion 5 has a characteristic that the compression allowable stress is larger than the tensile allowable stress.

On the other hand, for example, as shown in FIG. 11, the conventional joint structure 9 of the steel pipe pile shown in the above-mentioned Patent Document 2 has a ratio of Hc to Ht of Ht < 0.5 × Hc, and Hc is extremely large compared to Ht. Therefore, when the joint structure 9 of the conventional steel pipe pile is calculated by the ratio of the projection height Hc of the compression surface 31b and the compression surface 51b to the protrusion height Ht of the stretching surface 31a and the stretching surface 51a, the compression allowable stress is larger than the tensile allowance. 2 times the stress. Therefore, in the joint structure 9 of the conventional steel pipe pile, when the tensile allowable stress of the entire joint is equal to or higher than that of the steel pipe pile, the compression allowable stress of the entire joint is twice that of the steel pipe pile. Since the tensile allowable stress and the compressive allowable stress are the same in a general steel pipe pile, the conventional steel pipe pile joint structure 9 has a drawback that the compression allowable stress becomes an unnecessary design.

In the joint structure 7 of the steel pipe pile according to the present embodiment, as shown in Figs. 8 and 9, the stretched surface 31a of the outer portion 4 and the inner block portion 6 is fitted with the mountain portion 31 and the embedded mountain portion 51. The ratio of the protruding height Ht of the stretching surface 51a to the protruding height Hc of the compression surface 31b of the outer mountain portion 31 and the inlaid mountain portion 51 and the compression surface 51b is 0.5 or more and 0.9 or less. At this time, the joint structure 7 of the steel pipe pile is such that the protruding height Ht is smaller than the protruding height Hc, and in the axial direction, from the front end side A to the base end side B, the outer block portion 4 and the inner block portion 6 are on the shaft. The core direction Y is formed in a slightly tapered shape. Thereby, the joint structure 7 of the steel pipe pile makes the protruding height Ht smaller than the protruding height Hc, and can reduce the protruding height Ht to the same as the tensile allowable stress of the joint. Thereby, the compression allowable stress can be suppressed as an unnecessary design, so that the weight of the steel of the entire joint can be reduced as compared with the conventional joint structure 9 of the steel pipe pile.

Here, FIG. 16 shows a result of comparing the joint thickness ratio of the joint structure 7 of the steel pipe pile of the present embodiment and the conventional joint structure 9 of the steel pipe pile. In Fig. 16, the ratio of Hc to Ht (Ht/Hc) is the horizontal axis, and when the ratio of Hc to Ht is changed, the joint thickness ratio of the tensile allowable stress and the compressive allowable stress equivalent to the conventional steel pipe pile can be obtained. Vertical axis.

In Fig. 16, the joint thickness is set to Ht = 0.5 × Hc (corresponding to the examples of 2, 9, and 16 of Table 3) and set to the same tensile allowable stress and compressive allowable stress as the conventional steel pipe pile. When the ratio is the reference value, the value of the joint thickness ratio of the vertical axis is 1. The thickness of the joint is h (corresponding to D in Fig. 5), the thickness tp4 of the valley portion 53 in the fourth inner block portion 64, and the thickness tb1 of the valley portion 33 outside the first outer block portion 41. The total value of the predetermined gap CL.

In addition, in Fig. 16, the lower limit of the usual material specifications of the steel pipe pile is the SKK400 and SKK490 specified in JIS A 5525, and the upper limit of the material specification is the SM570 specified in JIS G 3106. Table 3 shows the numerical data of Fig. 16.

【table 3】

The joint structure 7 of the steel pipe pile is as shown in Fig. 16, and in the range of SKK400, SKK490 or SM570, especially in the range of 0.5×Hc≦Ht≦0.9×Hc, compared with the conventional joint structure 9 of the steel pipe pile, the joint The thickness ratio becomes smaller. Thereby, it is understood that the weight of the entire joint is small. Further, when the joint structure 7 of the steel pipe pile is designed in the range of 0.55 × Hc ≦ Ht ≦ 0.8 × Hc, the joint thickness ratio can be reduced by about 5.0% as compared with the conventional joint structure 9 of the steel pipe pile. As a result, the weight of the entire joint after processing can be reduced by about 3.5 to 4.0%.

Further, when the joint structure 7 of the steel pipe pile is designed in the range of 0.6 × Hc ≦ Ht ≦ 0.8 × Hc in SKK400 or SKK490, the joint thickness ratio can be reduced by about 10%. Further, in the SM570, when the design is in the range of 0.6 × Hc ≦ Ht ≦ 0.7 × Hc, the joint thickness ratio can be reduced by about 10%. Thereby, the joint structure 7 of the steel pipe pile is such that the ratio of the protruding height Ht to the protruding height Hc is 0.5 or more and 0.9 or less, and the protruding height Hc can be lowered to avoid the unnecessary design of the compression allowable stress. Thereby, compared with the conventional joint structure 9 of the steel pipe pile, the maximum allowable compressive and tensile and bending allowable stress can be obtained with a small amount of steel and the like. As a result, the weight and volume of the entire joint are reduced, the efficiency of the joining operation is improved, and the increase in the material cost of the joint is suppressed.

In the joint structure 7 of the steel pipe pile according to the present embodiment, each of the outer mountain portions 31 is relatively close to the protruding height Hc of the embedded portion 31 other than the second steel pipe pile 2, and is located beside the outer mountain portion 31. The ratio of the protrusion height Ht of the other externally embedded mountain portions 31 is 0.5 or more and 0.9 or less, and the projection height Hc of the inlaid mountain portion 51 of the first steel pipe pile 1 is relatively close to each of the inlaid mountain portions 51. The ratio of the protruding height Ht of the other inlaid mountain portions 51 located beside the inlaid mountain portion 51 is 0.5 or more and 0.9 or less.

Further, as shown in FIG. 17, a predetermined gap CL is usually present in the radial direction in the direction X orthogonal to the axis. Therefore, in consideration of the gap CL, in the relationship between the effective protrusion height Hc' (=Hc - 1.5 × CL) and Ht' (= Ht - 1.5 × CL), the relationship shown above (0.5 × Hc' should be established. ≦Ht'≦0.9×Hc').

Further, when the tensile force or the bending force acts, in order to prevent the separation between the outer mountain portion 31 and the inner mountain portion 51, it is preferable to set the lower limit value of the protruding height Ht. Here, in the bending test in which the outer diameter Dp of the steel pipe pile is changed to 800.0 mm and the Ht is changed to 2.4 mm, 3.3 mm, and 4.2 mm, as shown in Fig. 18, when Ht = 2.4 mm, The separation of the outer mountain portion 31 from the inlaid mountain portion 1551 determines the maximum allowable stress. On the other hand, when Ht=3.3 mm or more, the maximum allowable stress is determined according to the bearing pressure failure of the outer mountain portion 31 or the inlaid mountain portion 51. Therefore, if the outer mountain portion 31 is not separated from the inner mountain portion 51, but the damage state of the support pressure is as stable as possible, the lower limit of the protrusion height Ht is preferably Ht ≧ Dp / 250.

According to the joint structure 7 of the steel pipe pile according to the above-described embodiment, the thickness of the valley portion 33 outside the outermost fitting end side is smaller than the thickness of the inner valley portion 53 located at the most inscribed front end side, and The ratio of the plate thickness ensures the desired strength and also reduces the joint weight. Therefore, the joint weight of the steel pipe pile can be reduced, and the workability can be improved.

(Second embodiment) The second embodiment of the present invention will be described below, and basically corresponds to the modification of the first embodiment. Therefore, the same reference numerals as those used in the first embodiment are used, and the drawings are omitted. Show. In other words, the present embodiment basically has the same configuration as that of the above-described first embodiment. However, the thickness of the inner trough portion 53 closest to the first steel pipe pile 1 is the closest to the trough portion 33 which is closest to the second steel pipe pile 2. The ratio after the plate thickness is 0.84 or more and 0.94 or less.

19 is a graph in which the diameter-thickness ratio (Dp/tb1) of the outer diameter Dp of the conventional steel pipe pile and the thickness tb1 of the valley portion 33 outside the first outer block portion 41 is the horizontal axis. The thickness ratio (tb1/tp1) of the thickness tp1 of the inner valley portion 53 of the first inner block portion 61 and the thickness tb1 of the valley portion 33 outside the first outer block portion 41 is the vertical axis. Accordingly, when the material of the steel pipe is SM 570 or the thickness of the steel pipe is thick, the thickness of the outer slab is thick (the range of D/tp1 is 50 or less). Therefore, the thickness ratio of the inlaid valley portion 53 to the outer trough portion 33 is 0.94 or more, and there is almost no difference from the conventional structure. When the ratio of the diameter to the thickness is in the range of 50 to 150, since the weight can be reduced, the thickness ratio is preferably 0.84 or more and 0.94 or less. The ratio of the thickness of the outer valley portion 33 to the inner valley portion 53 is between the diameter and the thickness ratio, and a linear relationship as shown in the following formula 1 is established. (tb1/tp1)=0.99-0.001×(Dp/tb1) (Formula 1)

According to the joint structure 7 of the steel pipe pile according to the present embodiment, the ratio of the thickness of the steel pipe is set to the above range, whereby the influence on the joint weight can be further reduced than the thickness of the fitting end portion 5, and the thickness of the fitting end portion 3 can be made smaller. It can further reduce the weight of the entire joint. Therefore, the weight of the joint of the steel pipe pile can be further reduced.

<Third Embodiment> A third embodiment of the present invention will be described below. However, it is basically equivalent to the modification of the first embodiment. Therefore, the same reference numerals as those in the first embodiment are used, and the illustration is omitted. . In other words, the present embodiment basically has the same configuration as that of the above-described first embodiment. However, in each of the outer mountain portions 31, the protruding height of the inlaid portion 31 other than the second steel pipe pile 2 is relatively close to the outer casing. The ratio of the protruding heights of the other externally embedded mountain portions 31 beside the mountain portion 31 is 0.6 or more and 0.8 or less, and in each of the inlaid mountain portions 51, the inlaid mountain portions 51 of the first steel pipe pile 1 are relatively close to each other. The ratio of the protruding height to the protruding height of the other inlaid mountain portions 51 located beside the inlaid mountain portion 51 is 0.6 or more and 0.8 or less.

According to the joint structure of the steel pipe pile according to the present embodiment, the ratio of the protruding height of the mountain portion on the proximal end side to the protruding height of the mountain portion on the distal end side is in the above range, and the direction parallel to the axial line L can be sufficiently ensured. The strength on the top. Therefore, the strength of the joint as the steel pipe pile can be maintained, and the weight of the joint of the steel pipe pile can be reduced.

The above is a detailed description of the embodiments of the present invention, but the above-described embodiments are merely examples of specific examples when the present invention is implemented. Therefore, the technical scope of the present invention should not be construed as being limited thereto.

For example, the joint structure 7 of the steel pipe pile according to each of the above embodiments may be provided by cutting the end portions of the first steel pipe pile 1 and the second steel pipe pile 2, and providing the end portion of the first steel pipe pile 1 or the second steel pipe pile 2 The end 3 is embedded or the end 5 is embedded. Moreover, the inner end portion 5 may be provided in the first steel pipe pile 1, and the outer end portion 3 may be provided in the second steel pipe pile 2. Industrial availability

The joint construction of the steel pipe pile of the present invention ensures the desired strength and also reduces the joint weight. Therefore, the joint weight of the steel pipe pile can be reduced, and the steel pipe pile with improved workability can be provided. Therefore, the present invention has high industrial availability.

1‧‧‧1st steel pipe pile
2‧‧‧2nd steel pipe pile
3‧‧‧Applied end
31‧‧‧Exclusive mountain
31a‧‧‧ stretching surface
31b‧‧‧Compressed surface
32‧‧‧External ditch
33‧‧‧Exclusive Valley
38‧‧‧External Ministry
4‧‧‧Outer block
41‧‧‧1st outer block
42‧‧‧2nd outer block
43‧‧‧3rd outer block
44‧‧‧4th outer block
5‧‧‧Inlined end
51‧‧‧Inlaid hills
51a‧‧‧ stretching surface
51b‧‧‧Compressed surface
52‧‧‧Inset groove
53‧‧‧ embedded valley
58‧‧‧Inlined surplus section
6‧‧‧Internal block
61‧‧‧1st inner block
62‧‧‧2nd inner block
63‧‧‧3rd inner block
64‧‧‧4th inner block
7‧‧‧ Joint construction of steel pipe piles
A‧‧‧ front side
B‧‧‧ basal side
L‧‧‧Axis core wire
W‧‧‧ circumferential direction
X‧‧‧Axis core straight direction
Y‧‧‧Axis direction
Tb1...tb1,tb2,tb3,tb4‧‧‧thickness
Tp1, tp2, tp3, tp4‧‧‧ plate thickness Δb‧‧‧ difference in plate thickness of the outer block portion 4 adjacent to the axis direction of the outer core portion 4 Δp‧‧‧ in the axial direction Y phase The difference in plate thickness of the inner valley portion 53 of the adjacent inner block portion 6

Fig. 1 is a perspective view showing a joint structure of a steel pipe pile according to a first embodiment of the present invention. Fig. 2 is a cross-sectional view showing the outer end portion of the joint structure of the same steel pipe pile, and showing the cross section including the core wire. Fig. 3 is a partial cross-sectional view showing the outer end portion of the joint structure of the same steel pipe pile, and is a portion A of Fig. 2; Figure 4 is a side elevational view showing the inner end of the joint structure of the same steel pipe pile. Fig. 5 is a partial cross-sectional view showing the inner end portion of the joint structure of the same steel pipe pile, and is a portion B of Fig. 4; Fig. 6 is a perspective view showing the joint structure of the same steel pipe pile and inserted into the inner end portion of the outer fitting end portion. Fig. 7 is a perspective view showing a joint structure of the same steel pipe pile and rotating the inner end portion with respect to the outer end portion, and is a cross-sectional view of a portion of the outer end portion. Figure 8 is a partial cross-sectional view of the portion C of Figure 7, showing the tensile force acting on the stretched surface of the joint structure of the steel pipe pile. Figure 9 is a partial cross-sectional view of the portion C of Figure 7, showing the compressive force acting on the compression surface of the joint structure of the steel pipe pile. Fig. 10 is a partial cross-sectional view showing the joint structure of the same steel pipe pile, showing the thickness of each of the outer block portion and the inner block portion. Fig. 11 is a partial cross-sectional view showing a joint structure of a conventional steel pipe pile and showing the thickness of the outer block portion and the inner block portion. Fig. 12 is a partial cross-sectional view showing a modification of the joint structure of the steel pipe pile, showing a modified outer length portion and an inner length portion. Fig. 13 is a partial cross-sectional view showing a joint structure of a steel pipe pile, wherein (a) shows the thickness of the block portion and the inner block portion of the joint structure of the above embodiment, and (b) shows a conventional joint structure. The thickness of the outer block portion and the inner block portion, and (c) is a comparison of the plate thicknesses of (a) and (b). Fig. 14 is a view showing the relationship between the diameter-thickness ratio of the outer diameter of the steel pipe pile and the thickness of the outer end portion of the joint structure of the steel pipe pile according to the above embodiment, and the ratio of the maximum bending moment and the total plastic bending moment of the steel pipe pile; chart. Fig. 15A is a graph showing the relationship between the ratio of the diameter-thickness ratio of the inner end portion and the allowable stress ratio in the joint structure of the steel pipe pile according to the above embodiment, and showing the relationship between the ratio of the diameter-thickness ratio of the inner end portion to the allowable stress ratio. chart. Fig. 15B is a graph showing the relationship between the thickness-to-thickness ratio of the fitting end portion and the allowable stress ratio in the joint structure of the steel pipe pile according to the above embodiment, and showing the relationship between the aspect ratio of the outer end portion and the allowable stress ratio. chart. Fig. 16 is a view showing the relationship between the protrusion height of the compression surface and the protrusion height of the stretched surface in the joint structure of the steel pipe pile, and the joint thickness ratio of the tensile allowable stress and the compression allowable stress which are equivalent to the steel pipe pile. chart. Figure 17 is a partial cross-sectional view for explaining the relationship between the projection heights of the gaps in the joint structure of the steel pipe piles. Fig. 18 is a graph showing the results of a bending test after changing the joint height of the stretched surface in the joint structure of the same steel pipe pile. Fig. 19 is a graph showing the relationship between the aspect ratio and the thickness ratio of the joint structure of the steel pipe pile according to the second embodiment of the present invention.

1‧‧‧1st steel pipe pile

2‧‧‧2nd steel pipe pile

3‧‧‧Applied end

31‧‧‧Exclusive mountain

33‧‧‧Exclusive Valley

38‧‧‧External Ministry

4‧‧‧Outer block

41‧‧‧1st outer block

42‧‧‧2nd outer block

43‧‧‧3rd outer block

44‧‧‧4th outer block

5‧‧‧Inlined end

51‧‧‧Inlaid hills

53‧‧‧ embedded valley

58‧‧‧Inlined surplus section

6‧‧‧Internal block

61‧‧‧1st inner block

62‧‧‧2nd inner block

63‧‧‧3rd inner block

64‧‧‧4th inner block

7‧‧‧ Joint construction of steel pipe piles

Tb1, tb2, tb3, tb4‧‧‧ plate thickness

Tp1, tp2, tp3, tp4‧‧‧ plate thickness

Δb‧‧‧ The difference in thickness between the outer block portions 4 adjacent to the axis direction and the valley portion 33

Δp‧‧‧ the difference in sheet thickness of the inner valley portion 53 in the inner block portion 6 adjacent to the axial direction Y

X‧‧‧Axis core straight direction

Y‧‧‧Axis direction

A‧‧‧ front side

B‧‧‧ basal side

Claims (3)

A joint structure of a steel pipe pile, wherein a first steel pipe pile having an outer end portion and a second steel pipe pile having an inner end portion are connected in a state in which the outer end portion and the inner end portion share the same axial core line When the cross section is viewed along the axial line, the outer side of the outer end portion is provided with an outer diameter along the plurality of positions of the axial core line in a stepwise manner toward the second steel pipe pile. Each of the outer block portions has a portion adjacent to the second steel pipe pile and an outer valley portion adjacent to the outer mountain portion, and is along the outer side of the inner end portion The plurality of positions of the axial core wire are provided with the inner block portion so as to be tapered toward the first steel pipe pile, and each of the inner block portions has a relatively close proximity to the inner mountain portion of the first steel pipe pile, and Adjacent to the inlaid valley portion of the inlaid mountain portion, each of the inlaid mountain portions is locked in each of the aforementioned outer states in a state in which the inlaid end portion is inserted into the outer fitting end portion and relatively rotated about the axial core wire. Inlaid mountain, each of the aforementioned external mountains The ratio of the protruding height of the outer mountain portion located beside the outer mountain portion is 0.5 or more and 0.9 or less, respectively, in a relatively close to the protruding height of the outer mountain portion of the second steel pipe pile. In the inlaid portion, the protruding height of the inlaid mountain portion of the first steel pipe pile is relatively close to the height of the protruding height of the inlaid mountain portion located beside the inlaid mountain portion, and is 0.5 or more and 0.9 or less. The thickness of the outer trough portion closest to the second steel pipe pile is smaller than the thickness of the inner trough portion closest to the first steel pipe pile, and the inner inlaid valley closest to the first steel pipe pile The ratio of the thickness of the portion to the outer thickness of the outer trough portion of the second steel pipe pile is 0.84 or more. The joint structure of the steel pipe pile according to claim 1 is such that the ratio of the thickness of the inlaid valley portion closest to the first steel pipe pile is the closest to the thickness of the inlaid valley portion of the first steel pipe pile; Above, below 0.94. The joint structure of the steel pipe pile according to claim 1 or 2, wherein in each of the outer mountain portions, the protruding height of the outer mountain portion of the second steel pipe pile is relatively close to the outer side of the outer mountain portion The ratio of the protruding height of the externally embedded mountain portion is 0.6 or more and 0.8 or less, and each of the inlaid mountain portions is relatively close to the protruding height of the embedded mountain portion of the first steel pipe pile, and is located in the embedded mountain. The ratio of the protruding height of the aforementioned embedded mountain portion beside the portion is 0.6 or more and 0.8 or less.