Joint structure of steel pipe sheet pile

Abstract

To provide a joint structure of steel pipe sheet piles that enables reliable soil removal and cleaning work within a joint fitting portion, and solidification material injection work, and improves integrity of a joint member and a solidification material to improve joint strength.SOLUTION: A joint structure 1 of a steel pipe sheet pile comprises a male joint member 7 attached to an outer surface of one neighboring main pipe 5a, a female joint member 9 provided on an outer surface of the other neighboring main pipe 5b and fitted to the male joint member 7, and a solidification material 17 filled in a fitting portion between the male joint member 7 and the female joint member 9. The male joint member 7 is a member with a roughly T-shaped cross section that has a web portion 11 and a flange portion 13 and a protrusion 19 at a front surface of the flange portion 13. The female joint member 9 is a steel pipe member with a slit 9a, and when the joint is fitted, an area surrounded by the female joint member 9 is divided into three partitioned areas by the male joint member 7, and a size of each of the three partitioned areas when viewed from above is a circle with a diameter of 30 mm or more.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a joint structure of a steel pipe sheet pile. [Background technology]

[0002] One type of conventional foundation for underground structures is a steel pipe sheet pile foundation. As shown in Figure 6 of Patent Document 1, a steel pipe sheet pile foundation is constructed by arranging multiple steel pipe sheet piles in a circle and erecting them underground, and surrounding a certain area of ​​ground with a steel pipe sheet pile wall to form a foundation. Each steel pipe sheet pile is provided with a joint member for connecting the steel pipe sheet piles, and a steel pipe sheet pile wall is constructed by fitting the joint members of adjacent steel pipe sheet piles together. There are various types of joint structures for steel pipe sheet piles, one of which is shown in FIG. 5 of Patent Document 2, for example.

[0003] Figure 5 of Patent Document 2 shows a so-called LT-type joint structure, in which adjacent steel pipe sheet piles 61 are connected by fitting a protruding T-shaped steel 12 into a protruding L-shaped steel 13. In addition, concrete 40, which is a solidifying material, is poured into the fitting portion between the protruding T-shaped steel 12 and the protruding L-shaped steel 13.

[0004] When a horizontal external force, such as an earthquake, acts on a steel pipe sheet pile foundation constructed using the joint structure described above, a force acts on the joint members (protruding T-shaped steel 12 and protruding L-shaped steel 13) causing them to shift vertically in the longitudinal direction. As a result, the cement-based solidification material, such as mortar or concrete, placed in the fitting portion is subjected to a shear force in the longitudinal direction of the joint members.

[0005] To ensure sufficient strength for a steel pipe sheet pile foundation, it is desirable for the connected steel pipe sheet piles to resist external forces as a whole. However, if a shear force acts on the solidification material in the longitudinal direction of the joint members, causing the joint members to shift vertically in the longitudinal direction, the steel pipe sheet piles will not function as a single unit, and the strength of the foundation may be reduced.

[0006] In contrast to this, in the above-mentioned Patent Documents 1 and 2, protrusions are provided on the surface of the joint member to improve the adhesive force between the joint member and the solidifying material, thereby improving the strength of the joint member against shear force in the longitudinal direction. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 11-140863 [Patent Document 2] Patent No. 3368398 Summary of the Invention [Problem to be solved by the invention]

[0008] As mentioned above, in order to improve the strength of steel pipe sheet pile foundations, it is necessary to prevent the mating coupling members from shifting in the longitudinal direction of the coupling. Therefore, in the past, a protrusion was provided on the flange of the male coupling member to improve the adhesion between the solidification material filled in the mating portion and the male coupling member. In order to fully utilize the effect of improving adhesion due to the protrusions, it is desirable that the solidifying material be filled into the fitting portion without leaving any gaps.

[0009] In order to fill the solidification material without any gaps, it is necessary to completely remove the soil and sand from the mating section before filling it in. In the LT type joint structure described above, when the male joint member is mated with the female joint member, the area inside the female joint member is divided into three compartments by the male joint member, so it is necessary to remove the soil and clean each compartment separately to remove the soil and sand.

[0010] However, because the partitioned area separated by the male coupling member is very narrow, it is difficult to remove and clean the area, and there are cases where the soil cannot be completely removed. If the solidification material is filled in when the soil has not been sufficiently removed, the coupling member and the solidification material do not adhere sufficiently, and the expected joint strength cannot be obtained. In addition, the area formed on both sides of the web portion of the male coupling member is particularly small, so it is not possible to insert the injection pipe for injecting the solidification material, and there are cases where pouring the solidification material itself is difficult. The above-mentioned problem is not limited to the so-called LT type joint structure described above, but also applies to the so-called PT type joint structure consisting of a male joint member having a substantially T-shaped cross section and a female joint member having a slit formed in a steel pipe.

[0011] The present invention has been made to solve the above-mentioned problems, and aims to provide a joint structure for steel pipe sheet piles that allows for reliable soil removal and cleaning operations within the joint fitting portion, as well as solidification material injection operations, and that increases the integrity of the joint member and the solidification material, thereby improving the joint strength. [Means for solving the problem]

[0012] (1) The joint structure of a steel pipe sheet pile according to the present invention comprises a male joint member attached to the outer surface of one adjacent main pipe along the axial direction, a female joint member provided on the outer surface of the other adjacent main pipe along the axial direction and fitted to the male joint member, and a solidifying material filled in the fitting portion between the male joint member and the female joint member, The male coupling member is a generally T-shaped member having a web portion and a flange portion, and a protrusion on the front surface of the flange portion. The female coupling member is made of a steel pipe member having a slit, In a coupled state, the area surrounded by the female coupling member is divided into three compartments by the male coupling member, The size of each of the three partitioned areas in top view is a circle with a diameter of 30 mm or more.

[0013] (2) Furthermore, in the above (1), the distance from the front surface of the flange portion to the innermost part of the steel pipe member opposite the front surface is 20 times or more the height of the protrusion.

[0014] (3) Furthermore, in the above (1) or (2), the male coupling member is characterized in that the web length H of the web portion is 60 mm or more and satisfies the following formulas (1) and (2): Fs × t1 ≥ Fc × B (1) H / t1≦15.5 (2) where: Fc: Long-term allowable compressive stress of the solidified material Fs: Long-term allowable stress of the web (steel) B: Flange width of the flange H: Web length of the web section t1: web thickness

[0015] (4) In addition, in the above (1) or (2), the male coupling member is characterized in that the web length H of the web portion is 60 mm or more and satisfies the following formulas (1) and (3): Fs × t1 ≥ Fc × B (1) H / t1≦8.7 (3) where: Fc: Long-term allowable compressive stress of the solidified material Fs: Long-term allowable stress of the web (steel) B: Flange width of the flange H: Web length of the web section t1: web thickness [Effects of the Invention]

[0016] In the present invention, by making the size of each partitioned area in a top view a circle of φ30 mm or more, the workability of removing soil and cleaning work in each partitioned area, and the work of injecting solidification material in each partitioned area is improved. As a result, the solidification material filled in each partitioned area reliably adheres to the joint member, improving the unity between the solidification material and the joint member, and therefore the joint strength can be improved compared to conventional methods. [Brief explanation of the drawings]

[0017] [Figure 1] FIG. 1 is an explanatory diagram (part 1) of a joint structure of a steel pipe sheet pile according to an embodiment. [Figure 2] 2A to 2C are diagrams illustrating a method for manufacturing the male coupling member of FIG. 1. [Figure 3] FIG. 2 is an explanatory diagram (part 2) of a joint structure of a steel pipe sheet pile according to an embodiment. [Figure 4] FIG. 10 is an explanatory diagram (part 3) of a joint structure of a steel pipe sheet pile according to an embodiment. [Figure 5] FIG. 2 is an explanatory diagram of Example 1 of a joint structure of a steel pipe sheet pile according to an embodiment. [Figure 6] FIG. 10 is an explanatory diagram of Example 2 of the joint structure of the steel pipe sheet pile according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0018] A joint structure 1 for a steel pipe sheet pile according to one embodiment of the present invention (hereinafter simply referred to as the joint structure 1) will be described with reference to FIG. 1 is a diagram schematically illustrating a joint structure 1 according to the present embodiment, showing a top view of the fitting portion in a fitted joint state. In the figure, the x direction is the normal direction of the steel pipe sheet pile wall (the circumferential direction when the steel pipe sheet piles 3 are connected in a circular shape), the y direction is the direction perpendicular to the normal line of the steel pipe sheet pile wall (the radial direction when the steel pipe sheet piles 3 are connected in a circular shape), and the z direction is the axial direction of the steel pipe sheet piles 3. The above-mentioned "normal line" is an architectural term meaning the center line or axis in the extension direction of a structure, etc., and is different from the normal line commonly used as a mathematical term.

[0019] The steel pipe sheet pile 3 is composed of a main pipe 5a (5b) and a male joint member 7 and a female joint member 9 provided on the outer surface of the main pipe 5a (5b). Two adjacent steel pipe sheet piles 3 are the same, but for ease of identification, the main pipe of the steel pipe sheet pile 3 on the right side of the drawing is designated as 5a, and the main pipe of the steel pipe sheet pile 3 on the left side of the drawing is designated as 5b.

[0020] The male coupling member 7 is a member having a generally T-shaped cross section and including a web portion 11 and a flange portion 13, and is attached to the outer surface of one of the main pipes 5a along the axial direction. The female joint member 9 is made of a steel pipe member provided with a slit 9a, and is provided on the outer surface of the other main pipe 5b along the axial direction.

[0021] The slit 9a is provided along the axial direction of the members, and the male joint member 7 and the female joint member 9 are fitted together by inserting the web portion 11 of the male joint member 7 into this gap. The area surrounded by the female joint member 9 is filled with a solidifying material 17. As the solidifying material 17, cement-based materials such as mortar and concrete are mainly used. Geopolymers that can reduce CO2 emissions or concrete containing alkali-activated materials can also be used. To ensure joint strength, the compressive strength of the solidifying material is set to 20 N / mm 2 It is desirable to set it at this level. Furthermore, a water-stop material may be placed in the area filled with the solidification material 17. For example, by placing a gel-filled water-stop material in this area, it is possible to prevent the formation of water paths and prevent water leakage during and after construction.

[0022] Furthermore, a number of protrusions 19 extending in the flange width direction are provided on the front surface of the flange portion 13, i.e., the surface of the flange portion 13 facing the main pipe 5b, in the flange axial direction (see Figure 2). As mentioned above, these protrusions 19 function as shear connectors to improve the adhesion between the male coupling member 7 and the solidifying material 17 and integrate them. Furthermore, by providing such a protrusion 19, when a force is generated due to an earthquake or the like that shifts the male coupling member 7 and the female coupling member 9 in the axial direction (z direction), a bearing resistance is generated between the solidification material 17 and the protrusion 19. In this way, by providing the protrusions 19 on the flange portion 13, the adhesive force between the male coupling member 7 and the solidifying material 17 and the resistance to shear force in the z direction are improved.

[0023] The male coupling member 7 having the projection 19 as described above can be manufactured, for example, as follows. First, as shown in Figure 2, a protruding H-shaped steel 20 having striped protrusions 19 on the outer surface of the flange portion 13 is manufactured by roll forming. Then, this protruding H-shaped steel 20 is cut in half at the center of the web portion 11. In this way, the male joint member 7 having the protrusions 19 can be manufactured. The above method is preferable because it reduces manufacturing costs and time compared to a method of manufacturing the male coupling member 7 by cutting a steel plate with protrusions 19 formed thereon to produce the flange portion 13 and then welding the web portion 11 to the flange portion 13.

[0024] In the above, an example is shown in which the protrusion 19 is formed only on the front surface of the flange portion 13, but the protrusion 19 may also be provided on the rear surface of the flange portion 13 or on the web portion 11, or the protrusion 19 may be provided at the boundary between the web portion 11 and the flange portion 13. Furthermore, protrusions 19 may also be provided on the inner surface of the female coupling member 9 to enhance the unity of the female coupling member 9 and the solidifying material 17 .

[0025] The shape of the protrusions 19 is not limited to the striped shape shown in FIG. 2, but other shapes such as checkered rib shapes are also possible. Furthermore, when the protrusions 19 are formed by roll forming as described above, the protrusion height h (see FIG. 3) of the protrusions 19 is generally about 1 to 5 mm.

[0026] When the male coupling member 7 is fitted into the female coupling member 9, the area surrounded by the female coupling member 9 is partitioned by the web portion 11 and flange portion 13 of the male coupling member 7, forming three partitioned areas (the three areas surrounded by dashed lines in Figure 1). In this embodiment, the size of each of these three partitioned areas in top view is set to be equal to or larger than a circle with a diameter of 30 mm. Here, "size equal to or larger than a circle with a diameter of 30 mm" means a size that can contain a circle with a diameter of 30 mm. By setting the size of the partitioned area in this manner, the workability of the soil removal and cleaning operations when removing soil and sand is improved.

[0027] For example, by setting the size of each of the three compartment areas in Figure 1 to a circle with a diameter of 30 mm or larger, it becomes possible to place a pile saver (a rod-shaped polyester mesh bag filled with wood flour granules) in each compartment area. For example, when driving the steel pipe sheet pile 3 on the female joint member 9 side, by placing pile savers at positions corresponding to the three partitioned areas shown by dashed lines in Figure 1, it is possible to prevent sand and foreign objects from entering the female joint member 9 during construction. Then, when driving the steel pipe sheet pile 3 on the male joint member 7 side, it is advisable to insert the male joint member 7 into the gaps between the three pile savers placed inside the female joint member 9. Furthermore, by placing pile savers inside the fitting portion, the watertightness of the joint fitting portion is also improved.

[0028] Furthermore, by setting the size of each partitioned area to a circle of φ30 mm or more, an injection pipe (such as a grout hose) for filling the solidification material 17 can be inserted into each partitioned area. Therefore, the solidification material 17 can be reliably injected into all partitioned areas.

[0029] As described above, by setting the size of each partition area to a circle of φ30 mm or more and arranging a pile saver or the like on the female joint member 9 side when driving the steel pipe sheet pile 3, it is possible to eliminate or simplify the work of removing soil and cleaning after joint fitting, and furthermore, the work of injecting the solidification material 17 can be carried out efficiently and reliably, so that each partition area can be filled with the solidification material 17 without any gaps. Therefore, the unity between the solidification material 17 and the male joint member 7 and female joint member 9 is improved, and the strength of the joint fitting part is improved compared to conventional cases.

[0030] If the position of the male coupling member 7 shifts when the coupling is engaged, the size of each compartment area will also change, so it is necessary to drive the steel pipe sheet pile 3 so that the male coupling member 7 is positioned in a predetermined position. Therefore, it is preferable to use a spacing member that maintains a predetermined distance between the male coupling member 7 and the female coupling member 9, and drive the steel pipe sheet pile 3 while positioning the male coupling member 7.

[0031] Furthermore, even if spacing members or the like are used, it is conceivable that the actual size of the compartmentalized areas will be smaller than the design size due to construction errors. Therefore, it is preferable to set the size of each compartmentalized area to a circle of φ50 mm or more in advance, taking into consideration the possibility of misalignment of the male coupling component 7 due to construction errors. By setting the size of the compartmentalized areas to be larger, it becomes easier to ensure a space of φ30 mm or more in all compartmentalized areas, even if the position of the flange portion 13 is slightly misaligned from its original position due to construction errors.

[0032] However, if the size of each partition area is made excessively large, the male joint member 7 and female joint member 9 will become larger, which may increase the ground resistance when the steel pipe sheet pile 3 is driven into the ground. In particular, if the size in the normal direction (x direction) of the steel pipe sheet pile wall in each partition area (in Figure 1, the diameter of the semicircle shown by the dashed line) is increased, the length that the female coupling member 9 protrudes toward the main pipe 5a becomes longer, which tends to increase the penetration resistance when driving the steel pipe sheet pile 3. Therefore, it is desirable to set the size of the steel pipe sheet pile wall in the normal direction (x direction) in each partition area to 150 mm or less.

[0033] As described above, a bearing resistance against shear force in the z direction occurs between the solidification material 17 filled in the partition area on the front side of the flange portion 13, specifically, between the solidified body of the solidification material 17 and the protrusion 19. At this time, a tensile force acts on the solidification material, and if the solidification material is destroyed by this tensile force, the bearing resistance cannot be maximized. In other words, by preventing the solidification material from being destroyed first, the bearing resistance by the protrusion 19 can be maximized. This point will be explained in detail below using Figure 3.

[0034] In FIG. 3, if the protrusion height of the protrusion 19 is h and the bearing pressure strength (stress) of the solidified body formed by the solidifying material 17 is Fp, the bearing pressure resistance of the protrusion 19 per unit depth can be expressed as h×Fp. Also, if the distance from the front surface of the flange portion 13 to the innermost part of the female joint member 9 facing the front surface is L and the tensile strength (stress) of the solidified body is Ft, the tensile resistance of the solidified body in the partition region formed on the front surface side of the flange portion 13 (the region surrounded by the broken line in FIG. 3) can be expressed as L×Ft.

[0035] If the tensile resistance L×Ft of the solidified body in the portion surrounded by the broken line is lower than the bearing pressure resistance h×Fp of the protrusion 19, when a shear force in the z direction occurs, the solidified body will be destroyed first, so the effect of the bearing pressure resistance cannot be maximally exerted. Therefore, by setting the protrusion height h and the distance L so that h×Fp < L×Ft, the premature destruction of the solidified body can be prevented. When the solidified body is ordinary mortar or concrete, the ratio Fp / Ft of the bearing pressure strength Fp to the tensile strength Ft is approximately 20. Therefore, if the distance L is set to be 20 times or more the protrusion height h, h×Fp < L×Ft can be achieved. As a result, the premature destruction of the solidified body can be suppressed, so the effect of the bearing pressure resistance of the protrusion 19 can be maximally exerted, and the strength of the joint fitting portion can be improved.

[0036] As described above, by effectively expressing the bearing pressure resistance of the protrusion 19, the integrality of the flange portion 13 and the solidifying material 17 can be enhanced. However, on the other hand, if the rigidity and strength of the web portion 11 are insufficient, the expected joint strength may not be obtained. In particular, as shown in FIG. 4, when a compressive force in the normal direction (x direction) of the steel pipe sheet pile wall acts on the joint fitting portion, there is a concern that the web portion 11 may be compressed and destroyed, and thus the effects of the present embodiment cannot be maximally exerted. Therefore, in the present embodiment, it is preferable to provide the following regulations so that the web portion 11 is not prematurely destroyed by the compressive force acting on the joint fitting portion.

[0037] <000019In the male joint member 7 of this embodiment, the web length H of the web portion 11 is 60 mm or more, and satisfies the following formulas (1) and (2). Fs × t1 ≥ Fc × B (1) H / t1≦15.5 (2) where: Fc: Long-term allowable compressive stress of the solidified material Fs: Long-term allowable stress of the web (steel) B: Flange width of the flange H: Web length of the web section t1: web thickness

[0038] First, the web length H of the web portion 11 is set to 60 mm or more, taking into consideration the size of the two partition areas formed on both sides of the web portion 11, the plate thickness of the female coupling member 9, and the attachment allowance (welding, etc.) to the main pipe 5a.

[0039] The reason for setting formula (1) is as follows. As shown in Figure 4, when a compressive force in the x direction acts on the joint fitting portion, the compressive force acting on the web portion 11 increases depending on the flange width B of the flange portion 13 and the strength of the solidified body formed by solidifying the solidified material 17, and can therefore be expressed as the product of the flange width B and the design strength (long-term allowable compressive stress) Fc of the solidified body, Fc × B. On the other hand, the compressive strength of the web portion 11 can be expressed as the product of the plate thickness t1 of the web portion 11 and the design strength (long-term allowable stress) Fs of the web portion (steel material), ie, Fs×t1. From the above, when the male joint member 7 satisfies formula (1), the web portion 11 has sufficient compressive strength against the compressive force acting on the web portion 11, and the web portion 11 is less likely to be broken by compression.

[0040] Furthermore, formula (2) defines the width-thickness ratio of the web length H and the plate thickness t1 of the web portion 11, which is intended to prevent buckling (brittle fracture) in the elastic region of the web portion 11. The reason for defining the width-thickness ratio of the web portion 11 as in formula (2) is as follows. For example, in an architectural column structure, the width-thickness ratio of an FC-rank member to avoid brittle fracture is set to 15.5√(235 / F) or less (F is the yield strength of the member). The material used for the male joint member 7 is a general structural material, and its yield strength F is 235N / mm 2 ~450N / mm 2 Therefore, the width-thickness ratio in the FC rank is 15.5 to 11.2 or less. Therefore, in this embodiment, assuming the application of a material with a strength close to the minimum yield strength, the width-thickness ratio H / t1 of the web portion 11 is specified as in the above-mentioned formula (2). When the male coupling member 7 satisfies formula (2), buckling failure in the elastic region of the web portion 11 becomes less likely to occur.

[0041] As described above, when the male coupling member 7 satisfies the above-mentioned formulas (1) and (2), the web portion 11 can be prevented from being broken first, thereby maximizing the effects of this embodiment.

[0042] By satisfying formula (2), buckling failure in the elastic region of the web portion 11 can be prevented. However, even after the web portion 11 has been deformed plastically, the joint strength is rapidly reduced due to local buckling, so it is desirable to prevent such a reduction in strength. Therefore, in order to prevent a sudden decrease in strength due to local buckling of the web portion 11 after plastic deformation, the width-thickness ratio of the web portion 11 may be defined as in the following formula (3) instead of formula (2). H / t1≦8.7 (3)

[0043] For example, in a building column structure, the width-thickness ratio of an FB-rank member that ensures toughness is set to 12√(235 / F) or less (F is the yield strength of the member). As mentioned above, the yield strength F of the material used for the male joint member 7 is 235 N / mm 2 ~450N / mm 2 Therefore, the width-thickness ratio in the FB rank is 12.0 to 8.7 or less. Here, assuming the application of a material with a strength close to the maximum yield strength, the width-thickness ratio H / t1 of the web portion 11 is defined as in the above-mentioned formula (3). When the male joint member 7 satisfies formula (3), buckling fracture in the plastic region of the web portion 11 becomes less likely to occur.

[0044] As described above, according to the joint structure 1 of this embodiment, by making the size of each partitioned area formed in the joint fitting portion equal to or larger than a circle with a diameter of 30 mm when viewed from above, it is possible to reliably perform the work of removing soil and cleaning in each partitioned area, as well as the work of injecting the solidification material 17. As a result, the solidification material 17 filled in each partitioned area firmly adheres to the joint member, improving the unity between the solidification material 17 and the joint member, thereby improving the strength of the joint fitting portion compared to conventional cases.

[0045] In addition, by setting the distance L from the front surface of the flange portion 13 to the surface of the main pipe 5b facing that front surface to be more than 20 times the protrusion height h of the protrusion 19, it is possible to prevent premature destruction of the solidification material 17 adhering to the protrusion 19. Furthermore, by defining the shape of the male joint member 7, it is possible to prevent the web portion 11 from being destroyed first, which may occur when a compressive force is applied to the joint fitting portion. As described above, by preventing the solidifying material 17 from breaking first and the web portion 11 from breaking first, the effect of this embodiment can be maximized. [Example]

[0046] As preferred embodiments of the present invention, specific examples of a small pocket width (embodiment 1: FIG. 5) and a large pocket width (embodiment 2: FIG. 6) will be shown. 5 and 6 are the same drawings as FIG. 1 with dimensions added, and the sizes shown in the drawings do not correlate with the dimensional notation.

[0047] [Example 1] The dimensions of Example 1 are as shown in FIG. 5, and the main dimensions are as follows: Pipe thickness of female joint part 9: 11 mm Long-term allowable compressive stress of solidified material: Fc=8N / mm 2 Long-term allowable stress of the web (steel): Fs = 200 N / mm 2 Protrusion height: h=2.5mm Distance from the front of the flange to the innermost part of the female joint: L = 60 mm Flange width: B = 120 mm Web length: H=110mm Web thickness: t1 = 10 mm

[0048] Since h×20=2.5×20=50 mm and L=60 mm, the condition that L is 20 times or more the projection height h is met. Since Fs×t1=200×10=2000 and Fc×B=8×120=960, equation (1): Fs×t1≧Fc×B is satisfied. H / t1=110 / 10=11, which satisfies formula (2): H / t1≦15.5.

[0049] [Example 2] The dimensions of Example 2 are as shown in FIG. 6, and the main dimensions are as follows: Pipe thickness of female joint member 9: 13 mm Long-term allowable compressive stress of solidified material: Fc=8N / mm 2 Long-term allowable stress of the web (steel): Fs = 200 N / mm 2 Protrusion height: h=2.5mm Distance from the front of the flange to the innermost part of the female joint: L = 110 mm Flange width: B = 200 mm Web length: H=164mm Web thickness: t1 = 12 mm

[0050] Since h×20=2.5×20=50 mm and L=110 mm, the condition that L is 20 times or more the projection height h is met. Since Fs×t1=200×12=2400 and Fc×B=8×200=1600, equation (1): Fs×t1≧Fc×B is satisfied. H / t1=164 / 12=13.7, which satisfies formula (2): H / t1≦15.5. [Explanation of symbols]

[0051] 1. (Steel pipe sheet pile) joint structure 3 Steel pipe sheet piles 5a, 5b main 7 Male coupling member 9 Female coupling member 9a Slit 11 Web Department 13 Flange 17 Solidification material 19 Protrusion

Claims

1. A joint structure of a steel pipe sheet pile comprising: a male joint member attached to an outer surface of one adjacent main pipe along the axial direction; a female joint member provided on an outer surface of the other adjacent main pipe along the axial direction and fitted to the male joint member; and a solidified material filled in a fitting portion between the male joint member and the female joint member, The male coupling member is a generally T-shaped member having a web portion and a flange portion, and a protrusion on the front surface of the flange portion. The female coupling member is made of a steel pipe member having a slit, In a coupled state, the area surrounded by the female coupling member is divided into three compartments by the male coupling member, A joint structure for a steel pipe sheet pile, characterized in that the size of each of the three partition areas when viewed from above is a circle of φ30 mm or more.

2. 2. A steel pipe sheet pile joint structure according to claim 1, characterized in that the distance from the front surface of the flange portion to the innermost part of the female joint member facing the front surface is 20 times or more the protrusion height of the protrusion.

3. 3. A joint structure for a steel pipe sheet pile according to claim 1, characterized in that the web length H of the web portion of the male joint member is 60 mm or more and satisfies the following formulas (1) and (2): Fs × t1 ≧ Fc × B (1) H / t1≦15.5...(2) where: Fc: Long-term allowable compressive stress of the solidified material Fs: Long-term allowable stress of the web (steel) B: Flange width of the flange H: Web length of the web section t1: web thickness

4. 3. A joint structure for a steel pipe sheet pile according to claim 1, characterized in that the web length H of the web portion of the male joint member is 60 mm or more and satisfies the following formulas (1) and (3): Fs × t1 ≧ Fc × B (1) H / t1≦8.7 ... (3) where: Fc: Long-term allowable compressive stress of the solidified material Fs: Long-term allowable stress of the web (steel) B: Flange width of the flange H: Web length of the web section t1: web thickness

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