Steel pipe sheet pile wall joint set and method for manufacturing the same, and steel pipe sheet pile

Abstract

To provide a joint set for a steel pipe sheet pile wall and a production method thereof as well as a steel pipe sheet pile allowing work efficiency to be improved as improving damage resistance of a joint upon installation.SOLUTION: The present invention is a joint set for a steel pipe sheet pile wall including a pre-driven joint and a sequentially-driven joint. The sequentially-driven joint has: a fitting part of a circular shape or a polygonal shape, in a sectional shape, to which a tip on a pre-driven joint side opens; an arm part linearly extending from the fitting part; and a welding part extending toward a tip of the arm part in a fork shape. The pre-driven joint has a fitting part having: an inner space in a circular shape or a polygonal shape loosely fitted in the fitting part of the sequentially-driven joint in a sectional shape and a side surface opening part loosely fitted in the arm part of the sequentially-driven joint. This type of the joint set is produced through hot extrusion molding, and the pre-driven joint and the sequentially-driven joint are welded and joined in a longitudinal direction of the sheet pile to make the steel pipe sheet pile.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a joint set for a steel pipe sheet pile wall for connecting steel pipes constituting the steel pipe sheet pile wall, a manufacturing method thereof, and a steel pipe sheet pile provided with the joint set for the steel pipe sheet pile wall.

Background Art

[0002] Conventionally, as one of the means for constructing river and coastal revetments, earth retaining walls, etc., a steel pipe sheet pile structure formed by continuously driving a plurality of steel pipes has been used. A steel pipe sheet pile is a member in which a joint is attached to a steel pipe by welding, and a wall structure can be constructed by connecting the steel pipes to each other. Furthermore, the steel pipe sheet pile has features such as the ability to freely set the rigidity of the wall body and the planar arrangement location by changing the steel pipe diameter, plate thickness, and attachment position of the joint, and the ability to be used as a foundation structure by utilizing the supporting force of the steel pipe.

[0003] Conventionally, as joints for steel pipe sheet piles, approximately three types of combined joints (L-T joints, P-P joints, P-T joints) have been used. In some cases, a filler such as mortar is filled into the joint for the purpose of ensuring water tightness and improving shear strength. In such cases, after driving the steel pipe sheet pile, the inside of the joint is washed, and then a tremie pipe is inserted into the inner space of the joint to fill it with a filler such as mortar. This procedure is generally adopted.

[0004] Here, the general structure of the joint section and a simple installation procedure for steel sheet piles having PT joints will be explained, with the structure of the joint section described in Patent Document 1 shown in Figure 5. Note that in Figure 5, the joint according to the prior art does not have a watertight plate 59, while the invention described in Patent Document 1 employs a watertight plate 59. In typical steel sheet piles 51 and 56 having PT joints 50, a leading joint (joint pipe) 53 and a trailing joint (CT-shaped steel) 58 are welded together at two locations in the circumferential direction of a single sheet pile steel pipe 52 and 57 along its entire length to form a single steel sheet pile 51 or 56. Next, the installation procedure for steel sheet piles 51 and 56 into the ground will be explained starting from the steps after the leading steel sheet pile 51 has been installed. The trailing steel pipe sheet pile 56 is driven to the same ground depth as the trailing steel pipe sheet pile 51, by using the opening 55 of the leading joint (joint pipe) 53 to fit the trailing joint 58 into the internal space 54 of the leading joint (joint pipe) 53.

[0005] Next, using Figure 5, the problems of conventional steel sheet piles with PT joints will be explained. As described above, the leading joint pipe 53 is provided with a slit-shaped opening 55 for inserting the base of the trailing joint (CT-shaped steel) 58. Therefore, during the excavation process at the bottom of the joint pipe 53 when driving the steel sheet piles 51 and 56, and during the cleaning process inside the joint pipe 53 after driving, surrounding mud and muddy water flow into the joint pipe 53 through this opening 55. This is a major problem because it significantly reduces the effectiveness of the work required before filling with the packing material 60, such as removing soil from inside the joint pipe 53 and cleaning the inside. To address this problem, the invention described in Patent Document 1, as shown in Figure 5, attempts to block the inflow of muddy water and muddy soil from the opening 55 into the internal space 54 of the joint pipe 53 by providing a watertight plate 59 on the CT-shaped steel 58.

[0006] Furthermore, the cleaning of the joints using water jets or air lifters after the driving of steel pipe sheet piles has been problematic because the work itself is time-consuming and it is difficult to completely clean the soil when the depth is great. As a solution to these problems, for example, Patent Document 2 discloses a joint for a waterproof panel that is similar to, but not for, steel pipe sheet piles. Specifically, in the invention described in Patent Document 2, as shown in Figure 6, an opening sealing plate 74 is welded to the joint pipe 72 attached to the waterproof panel body 71 of the waterproof panel 70 that is driven in first, to seal a slit-shaped opening 73 provided on its side for fitting a subsequent joint. In addition, in the invention described in Patent Document 2, a cover member 75 for preventing soil inflow is installed at the lower end of the joint pipe 72. According to the invention described in Patent Document 2, when the subsequent waterproofing panel 70 is cast, the subsequent joint is fitted into the preceding joint while cutting the opening sealing plate 74 of the preceding joint, thereby preventing soil and sand from entering the joint portion of the waterproofing panel and allowing the waterproofing material to exhibit a predetermined waterproofing performance. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2003-055958 [Patent Document 2] Japanese Patent Publication No. 2008-014004 [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] However, in the invention described in Patent Document 1, as shown in Figure 7, the space occupied by the fitting portion of the trailing joint (CT-shaped steel) 58 within the internal space 54 of the leading joint (joint pipe) 53 occupies a large area 82 that obstructs the insertion of the tremie pipe. As a result, the range (inscribed circle) 80 in which the tremie pipe can be inserted becomes smaller, which leads to the problem of increased mortar filling time.

[0009] Furthermore, when applying an invention such as the one described in Patent Document 2, which involves installing a cover member 75 for preventing soil and sediment inflow at the lower end of a joint pipe 72, to a joint of a steel sheet pile, there is a problem that the resistance force received by the joint from the ground when the steel sheet pile is driven increases in proportion to the area of ​​the cover member, thus increasing the risk of deformation or damage to the joint.

[0010] Thus, the required joint cross-section for steel pipe sheet pile joints presents a dilemma: a larger size is needed for ease of filling with mortar and other filling materials, while a smaller size is required for ease of installation considering resistance from the ground. Achieving both of these requirements is difficult.

[0011] Therefore, the present invention has been made in view of the above-mentioned problems, and aims to provide a joint set for steel pipe sheet pile walls, a method for manufacturing the same, and a steel pipe sheet pile on which the joint set for steel pipe sheet pile walls is installed, which can improve the damage resistance of the joint during driving and increase work efficiency by maximizing the internal space of the joint without increasing the cross-sectional area of ​​the joint. [Means for solving the problem]

[0012] [1] A joint set for steel pipe sheet pile walls, consisting of a leading joint and a trailing joint, A joint set for steel pipe sheet pile walls, wherein the trailing joint has a cross-sectional shape having a circular or polygonal fitting portion with an opening at the tip of the leading joint, an arm portion extending linearly from the fitting portion, and a bifurcated welded portion at the tip of the arm portion, and the leading joint has a cross-sectional shape having a fitting portion having a circular or polygonal internal space into which the fitting portion of the trailing joint is loosely fitted, and a side opening into which the arm portion of the trailing joint is loosely fitted.

[0013] [2] A steel pipe sheet pile wall joint set according to [1], having a fitting surface sealing projection on the inner circumferential surface of the fitting portion of the preceding joint near the side opening or on the outer circumferential surface of the fitting portion of the succeeding joint near the arm portion.

[0014] [3] The steel pipe sheet pile wall joint set according to [1] or [2], wherein the preceding joint further comprises an arm portion extending linearly in cross-sectional shape from the side of the fitting portion and a bifurcated welded portion extending from the tip of the arm portion.

[0015] [4] A steel pipe sheet pile wall joint set according to any one of [1] to [3], wherein, when the leading joint and the trailing joint are fitted together, a position adjustment projection is provided on one or both of the two plate surfaces of the arm portion of the trailing joint, positioned on the plate surface adjacent to the fitting portion of the trailing joint, straddling the side opening of the fitting portion of the leading joint.

[0016] [5] A steel pipe sheet pile wall joint set according to any one of [1] to [4], wherein the steel pipe forming the fitting portion of the preceding joint is a steel pipe having recesses at predetermined intervals in the longitudinal direction, or a steel pipe having recesses at predetermined intervals in both the longitudinal and circumferential directions.

[0017] [6] A steel pipe sheet pile wall joint set according to any of [1] to [5], wherein the average value HA of the Vickers hardness at any cross-sectional position of the fitting portion, the arm portion, and the welded portion, and the average value HB of the Vickers hardness at the cross-section of the connection portion between the fitting portion and the arm portion, and the connection portion between the arm portion and the welded portion, satisfy 0.9 ≤ HA / HB ≤ 1.1.

[0018] [7] A method for manufacturing a steel pipe sheet pile wall joint set, comprising the step of manufacturing either or both of the preceding joint and the succeeding joint that constitute the steel pipe sheet pile wall joint set described in any of [1] to [6] above by hot extrusion molding through dies machined to their respective cross-sectional shapes.

[0019] [8] A steel sheet pile to which a steel sheet pile wall joint set described in any of [1] to [6] above is welded together. [Effects of the Invention]

[0020] According to the configuration of the present invention, by maximizing the internal space of the joint without increasing the cross-sectional area of the joint, it is possible to provide a joint set for a steel pipe sheet pile wall that can improve the damage resistance of the joint during the driving of the steel pipe sheet pile and enhance the working efficiency.

Brief Description of the Drawings

[0021] [Figure 1] It is a figure which shows in sectional drawing the joint set 1 for steel pipe sheet pile walls which concerns on Embodiment 1. [Figure 2] It is a figure which shows in sectional drawing the joint set 2 for steel pipe sheet pile walls which concerns on the modification of Embodiment 1. [Figure 3] It is a figure which shows in sectional drawing the joint set 3 for steel pipe sheet pile walls which concerns on Embodiment 2. [Figure 4] It is a figure which shows in sectional drawing the joint set 4 for steel pipe sheet pile walls which concerns on Embodiment 3. [Figure 5] It is a figure which shows in sectional drawing the structure of the P-T joint of the steel pipe sheet pile provided witha water shielding plate on the CT steel according to the prior art. [Figure 6] It is a figure which shows in perspective view the structure in which a lid member for preventing the inflow of earth and sand is installed at the lower end of a joint pipe according to the prior art. [Figure 7] It is a figure which explains in sectional drawing the insertable range of a tremie pipe in the P-T joint of the steel pipe sheet pile according to the prior art.

Modes for Carrying Out the Invention

[0022] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the embodiments shown below, a joint set for a steel pipe sheet pile wall (hereinafter, also simply referred to as a joint set) composed of a preceding joint and a following joint that connects a pair of adjacent steel pipe sheet piles constituting the steel pipe sheet pile wall will be described. In addition, the driving performance of the steel pipe sheet pile provided with such a joint set and the water shielding property (also referred to as water stopping property) of the joints of the steel pipe sheet pile wall will be described as appropriate. In the embodiments shown below, the same or common parts are denoted by the same reference numerals in the drawings, and the description thereof will not be repeated. Further, the present invention is not limited to the following embodiments.

[0023] (Embodiment 1) Figure 1 is a cross-sectional view perpendicular to the longitudinal direction showing the state in which the leading joint 10 and trailing joint 20 of the steel pipe sheet pile wall joint set 1 according to Embodiment 1 are fitted together. Note that in Figure 1, the sheet pile steel pipes to which the steel pipe sheet pile wall joint set 1 is welded together are not shown.

[0024] The steel pipe sheet pile wall joint set 1 according to Embodiment 1 is A steel pipe sheet pile wall joint set 1 consisting of a leading joint 10 and a trailing joint 20, The trailing joint 20 has a cross-sectional shape that includes a circular or polygonal fitting portion 22 with an opening at the tip on the leading joint side, an arm portion 26 extending linearly from the fitting portion 22, and a bifurcated welded portion 28 at the tip of the arm portion 26. The leading joint 10 has a cross-sectional shape that includes a fitting portion 12 which has a circular or polygonal internal space 30 that loosely fits with the fitting portion 22 of the trailing joint 20, and a side opening 14 that loosely fits with the arm portion 26 of the trailing joint 20.

[0025] These leading joints 10 and trailing joints 20 are welded together at two positions in the circumferential direction of the steel pipe cross-section on the side of a steel pipe for sheet piles (hereinafter also simply referred to as a steel pipe or sheet pile steel pipe), along the entire length of the sheet pile steel pipe, to form a steel pipe sheet pile. Furthermore, by continuously driving these steel pipe sheet piles and filling the internal space of the joints with a waterproofing material, a watertight steel pipe sheet pile wall is constructed.

[0026] The trailing joint 20 has a circular or polygonal fitting portion 22 in cross-section, with the tip on the leading joint side being open. By making the tip of the fitting portion 22 on the leading joint side open in cross-section, the internal space 30 of the joint set 1 in the fitted state can be made into a single, integrated internal space, with the internal space of the leading joint 10 and the internal space of the trailing joint communicating with each other. Furthermore, by filling this internal space 30 with a filler material such as mortar, high shear strength and high watertightness of the joint can be obtained. The circular or polygonal cross-sectional shape of the fitting portion 22 will be explained in conjunction with the fitting portion 12 of the leading joint 10, which will be described later.

[0027] Furthermore, the trailing joint 20 has a cross-sectional shape that includes an arm portion 26 extending linearly from the fitting portion 22. The presence of such an arm portion 26 makes it possible to reduce the steel weight per unit width of the joint in the extension direction of the steel pipe sheet pile wall.

[0028] The trailing joint 20 has a bifurcated weld 28 at the tip of the arm portion 26. By using a bifurcated weld 28, the distance between the welds on both sides can be increased compared to the joint between the CT-shaped steel and the sheet pile steel pipe in conventional PT joints (see Figure 5), making welding easier. Furthermore, the increased distance between the welds on both sides also improves welding quality, such as suppressing thermal deformation during welding. The shape of the weld is designed to allow for the implementation of the expected welding method with the sheet pile steel pipe (flare welding or fillet welding).

[0029] The leading joint 10 has a fitting portion 12 that has a circular or polygonal internal space 30 (inner circumferential surface 13) in cross-sectional shape that loosely fits with the fitting portion 22 (outer circumferential surface 23) of the trailing joint 20. In other words, both the leading joint 10 and the trailing joint 20 have a circular or polygonal cross-sectional shape, and have fitting portions 12 and 22 that have a reciprocal relationship in shape and size that allow them to loosely fit together. Therefore, compared to conventional PT joints (see Figure 5), the internal space 30 can be maximized without increasing the cross-sectional area of ​​the joint. As a result, the diameter of the insertable tremie pipe can be maximized, and the efficiency of filling work with mortar or other fillers can be improved.

[0030] Furthermore, the interrelationship of the shape and size of the fitting portions of the leading joint 10 and the trailing joint 20 increases the path length between the inner circumferential surface 13 of the fitting portion 12 of the leading joint 10 and the outer circumferential surface 23 of the fitting portion 22 of the trailing joint 20 compared to conventional PT joints (see Figure 5). Therefore, when filling with a filler material such as mortar, it has the effect of suppressing the outflow of the filler material before it hardens when driving steel pipe sheet piles. In addition, even when mortar is not filled, the increased path length provides the secondary effect of improving watertightness. It is also thought that watertightness is improved by the clogging of the infiltration path with soil and sediment carried by the water flow.

[0031] Furthermore, the fitting portion 12 of the leading joint 10 has a cross-sectional shape that includes a side opening 14 into which the arm portion 26 of the trailing joint 20 is loosely fitted. This side opening 14 is necessary for the arm portion 26 of the trailing joint 20 to be loosely fitted and for adjacent steel sheet piles to be connected. The extension direction of the steel sheet pile wall can be adjusted by adjusting the relationship between the welding joint position of the fitting portion 12 of the leading joint 10 to the sheet pile steel pipe and the opening position of the side opening 14 in a cross-section perpendicular to the longitudinal direction of the steel sheet pile.

[0032] Here, it is preferable that the tip of the trailing joint 20 on the fitting side has a cross-sectional shape that extends beyond the centroid of a figure assuming a circular or polygonal shape where the tip of the fitting portion 22 is not open, in order to facilitate adjustment of the fitting position. When such a trailing joint 20 is fitted into the leading joint 10, the tip of the trailing joint 20 on the fitting side does not come into contact with the inner circumferential surface 13 of the leading joint 10 and penetrate deeply, and as a result, the reduction in the cross-sectional area of ​​the internal space 30 can be suppressed.

[0033] The steel pipe forming the fitting portion 12 of the leading joint 10 may be a stepped steel pipe having grooves at predetermined intervals in the longitudinal direction, or a dimpled steel pipe having grooves at predetermined intervals in both the longitudinal and circumferential directions, although this is not shown in the illustration. In this case, the adhesion force of the mortar is improved by increasing the surface area of ​​the steel pipe, and the shear strength of the steel pipe used as the leading joint 10 can be significantly improved.

[0034] Next, the manufacturing method of the steel pipe sheet pile wall joint set 1 according to Embodiment 1, and the material of the steel pipe sheet pile wall joint set 1 manufactured by this manufacturing method will be described.

[0035] The manufacturing method for the steel pipe sheet pile wall joint set 1 according to Embodiment 1 is not particularly limited, and can be manufactured by, for example, general processes such as welding a steel pipe and a strip plate. However, the joint set 1 manufactured in this manner may undergo deformation of various parts due to welding heat during manufacturing. Furthermore, in such a joint set 1, areas where toughness is locally reduced due to welding heat-affected zones during manufacturing may become the starting point of failure during use or construction.

[0036] Therefore, a preferred manufacturing method for the joint set 1 according to Embodiment 1 is a manufacturing method in which either one or both of the leading joint 10 and the trailing joint 20 are manufactured by hot extrusion molding through dies machined to their respective cross-sectional shapes. The joint set 1 manufactured in this way can produce a joint structure with the final cross-sectional shape without the need for machining and welding. Furthermore, with hot extrusion molding, in addition to the basic joint structure, it is possible to add additional protrusions or change the surface shape as needed. Thus, with hot extrusion molding, it is possible to reduce processing costs compared to conventional manufacturing methods that combine general machining and welding.

[0037] In a joint set 1 manufactured integrally by hot extrusion molding, which is a preferred manufacturing method, the strength (hardness) and toughness of the material are generally the same in each part, such as the mating parts 12 and 22, the arm parts 16 and 26, and the welded parts 18 and 28, as well as in the connections between each part. There are no parts where the strength (hardness) changes locally or where the toughness is low, as is the case with joint sets 1 manufactured by general machining and welding.

[0038] Whether or not the joint set 1 according to Embodiment 1 was manufactured by hot extrusion molding can be determined by checking whether the material is generally uniform throughout the joint, and this can be specifically confirmed by the following material test. That is, for the joint set 1 for steel pipe sheet pile walls according to Embodiment 1 that is the subject of the test, the average value HA of Vickers hardness is determined at any cross-sectional position of the fitting parts 12, 22, arm parts 16, 26, and welded parts 18, 28. Furthermore, the average value HB of Vickers hardness is determined at the cross-sections of the connection parts between the fitting parts 12, 22 and the arm parts 16, 26, and the connection parts between the arm parts 16, 26 and the welded parts 18, 28. Then, the manufacturing method of the joint set 1 according to Embodiment 1 can be confirmed by checking whether these HA and HB satisfy 0.9 ≤ HA / HB ≤ 1.1.

[0039] (modified version) Figure 2 is a cross-sectional view showing a modified joint set 2 for a steel pipe sheet pile wall according to Embodiment 1. The modified joint set 2 will be described with reference to Figures 1 and 2.

[0040] As shown in Figure 2, the modified joint set 2 differs from the joint set 1 according to Embodiment 1 shown in Figure 1 in that it has a mating surface sealing projection 32. The position where the mating surface sealing projection 32 is provided is near the side opening 14 on the inner circumferential surface 13 of the mating portion 12 of the leading joint 10, or near the arm portion 26 on the outer circumferential surface 23 of the mating portion 22 of the trailing joint 20. The other configurations are substantially the same as those of Embodiment 1.

[0041] Even when configured as described above, the modified joint set 2 can achieve substantially the same effects as the joint set 1 according to Embodiment 1.

[0042] In addition, the placement of the fitting surface sealing projection 32 at a predetermined position provides secondary effects such as suppressing the outflow of filler materials such as mortar before they solidify during the driving of steel sheet piles, and improving watertightness when using steel sheet pile walls.

[0043] The fitting surface sealing projection 32 on the fitting set 2 can be manufactured by a general manufacturing method such as welding steel wire to the fitting set 1 as shown in Figure 1. However, hot extrusion molding has the advantage of extremely high freedom in shape, and it can also be adopted as a preferred manufacturing method for the fitting surface sealing projection 32 on the fitting set 2. That is, with hot extrusion molding, the cross-sectional shape of the fitting surface sealing projection 32 can be additionally added to the die position corresponding to the predetermined position where the fitting surface sealing projection 32 is to be placed, and it is preferable to manufacture a fitting set 2 having a generally uniform material throughout the fitting without significantly increasing material costs and processing costs.

[0044] (Embodiment 2) Figure 3 is a cross-sectional view showing a joint set 3 for steel pipe sheet pile walls according to Embodiment 2. The joint set 3 according to Embodiment 2 will be described with reference to Figures 1 and 3.

[0045] As shown in Figure 3, the joint set 3 according to Embodiment 2 differs from the joint set 1 according to Embodiment 1 in that the leading joint 10 is further provided with an arm portion 16 that extends linearly in cross-sectional shape from the side surface of the fitting portion 12, and a bifurcated weld portion 18 at the tip of the arm portion. The other configurations are substantially the same as those of Embodiment 1. Note that the dimensions and shape of the arm portion 16 and weld portion 18 of the leading joint 10 do not need to be the same as the dimensions and shape of the arm portion 26 and weld portion 28 of the trailing joint 20.

[0046] Even when configured as described above, the joint set 3 according to Embodiment 2 can obtain substantially the same effects as the joint set 1 according to Embodiment 1.

[0047] In addition, by further providing the leading joint 10 with an arm portion 16 extending linearly in cross-sectional shape from the side of the fitting portion 12, and a bifurcated welding portion 18 at the tip of the arm portion, the welding of the leading joint 10 to the sheet pile steel pipe of the leading steel pipe sheet pile becomes significantly easier compared to the joint set 1 according to Embodiment 1. Furthermore, since the welding position can be separated from the fitting portion 12 by the arm portion 16, the effect of reducing the influence of welding thermal deformation on the fitting portion 12 is also obtained.

[0048] Regarding the manufacturing method of the joint set 3, similar to the joint set 1 according to Embodiment 1, either a manufacturing method combining general machining and welding, or a manufacturing method using hot extrusion molding can be employed.

[0049] (Embodiment 3) Figure 4 is a cross-sectional view showing a joint set 4 for steel pipe sheet pile walls according to Embodiment 3. The joint set 4 according to Embodiment 3 will be described with reference to Figures 2 and 4.

[0050] As shown in Figure 4, the joint set 4 according to Embodiment 3 differs from the joint set 2 according to a modification of Embodiment 1 in that it is provided with a position adjustment projection 34. The position of the position adjustment projection 34 is located on one or both sides of the arm portion 26 of the trailing joint 20, straddling the side opening 14 of the fitting portion 12 of the leading joint 10, and close to the fitting portion 12 of the trailing joint 20. This allows the position of the fitting portion 12 of the leading joint 10 and the position of the fitting portion 22 of the trailing joint 20 to fall within a predetermined allowable variation range when the leading joint 10 and the trailing joint 20 are fitted together. The other configurations are substantially the same as the modification of Embodiment 1.

[0051] Even when configured as described above, the joint set 4 according to Embodiment 3 provides substantially the same effects as the joint set 2 according to a modification of Embodiment 1. In addition, when the leading joint 10 and the trailing joint 20 are fitted together, it becomes significantly easier to ensure that the position of the fitting portion 12 of the leading joint 10 and the position of the fitting portion 22 of the trailing joint 20 fall within a predetermined allowable variation range, compared to the case of the joint set 2 according to a modification of Embodiment 1.

[0052] Furthermore, in the case of joint sets 1, 2, and 3, in order to prevent the trailing joint 20 from penetrating too deeply into the fitting portion 12 of the leading joint 10 when the joints are fitted, it was preferable that the tip of the fitting portion side of the trailing joint 20 have a cross-sectional shape such that the tip of the fitting portion 22 extends beyond the centroid position of a predetermined figure. However, in the joint set 4 according to Embodiment 3, there is no such concern. This is because the joint set 4 is provided with a position adjustment projection 34, so the shape of the fitting portion 22 is not limited from this viewpoint. Therefore, in the joint set 4, as long as the function as a joint set is ensured, the internal space 30 of the joint can be maximized by miniaturizing the fitting portion 22 as shown in Figure 4, and consequently the diameter of the insertable tremie pipe can be maximized, further improving the efficiency of the filling work of filler materials such as mortar.

[0053] Regarding the manufacturing method of the joint set 4, similar to the joint set 2 in the modified embodiment of Embodiment 1, either a manufacturing method combining general machining and welding, or a manufacturing method using hot extrusion molding can be employed. [Explanation of Symbols]

[0054] 1, 2, 3, 4 Steel pipe sheet pile wall connector set (connector set) 10 Leading joint 12 Fitting part 13 Inner surface 14 Side opening 16 Arm section 18 Welded section 20 Rear joint 22 Fitting part 23 Outer surface 26 Arm section 28 Welded section 30 Interior space 32 Mating surface sealing protrusion 34 Position adjustment protrusion 50 Fittings (PT Fittings) 51 Steel pipe sheet piles 52 Sheet Pile Steel Pipes 53 Leading joint (joint pipe) 54 Interior space 55 Opening 56 Steel pipe sheet piles 57 Sheet Pile Steel Pipe 58. Rear joint (CT-shaped steel) 59 Waterproofing plate 60 Filling material 70 Waterproof Panel 71 Waterproof panel body 72 Leading Joint Pipe 73 Slit-shaped opening 74 Opening sealing plate 75 Lid member 80. Ptolemy tube insertion range (inscribed circle) 82 Ptolemy tube insertion inhibition range

Claims

1. A joint set for steel pipe sheet pile walls, consisting of a leading joint and a trailing joint, The aforementioned trailing joint has a cross-sectional shape comprising a circular or polygonal fitting portion with an opening at the tip of the preceding joint, an arm portion extending linearly from the fitting portion, and a bifurcated welded portion at the tip of the arm portion. The preceding joint has a cross-sectional shape that includes a fitting portion having a circular or polygonal internal space into which the fitting portion of the succeeding joint is loosely fitted, and a side opening into which the arm portion of the succeeding joint is loosely fitted. A joint set for steel pipe sheet pile walls, having a fitting surface sealing projection on the inner circumferential surface of the fitting portion of the preceding joint near the side opening, or on the outer circumferential surface of the fitting portion of the succeeding joint near the arm portion.

2. The steel pipe sheet pile wall joint set according to claim 1, wherein the preceding joint further comprises an arm portion extending linearly in cross-sectional shape from the side surface of the fitting portion and a bifurcated welded portion extending from the tip of the arm portion.

3. A joint set for a steel pipe sheet pile wall according to claim 1 or 2, wherein, when the leading joint and the trailing joint are fitted together, a position adjustment projection is provided on one or both of the two plate surfaces of the arm portion of the trailing joint, positioned on the plate surface adjacent to the fitting portion of the trailing joint, straddling the side opening of the fitting portion of the leading joint.

4. The steel pipe sheet pile wall joint set according to any one of claims 1 to 3, wherein the steel pipe forming the fitting portion of the preceding joint is a steel pipe having recesses at predetermined intervals in the longitudinal direction, or a steel pipe having recesses at predetermined intervals in both the longitudinal and circumferential directions.

5. The average value HA of the Vickers hardness at any cross-sectional position of the fitting portion, the arm portion, and the welded portion, The average value HB of the Vickers hardness in the cross-sections of the connection between the fitting portion and the arm portion, and the connection between the arm portion and the welded portion, A joint set for steel pipe sheet pile walls according to any one of claims 1 to 4, satisfying 0.9 ≤ HA / HB ≤ 1.

1.

6. A method for manufacturing a steel pipe sheet pile wall joint set, comprising the step of manufacturing either or both of the preceding joint and the succeeding joint constituting the steel pipe sheet pile wall joint set according to any one of claims 1 to 5 by hot extrusion molding through dies machined to their respective cross-sectional shapes.

7. A steel pipe sheet pile having been welded together with the steel pipe sheet pile wall joint set described in any one of claims 1 to 5.

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