Joint structure of steel pipe sheet pile

Abstract

To provide a joint structure of steel pipe sheet piles that can improve the strength against the shearing stress in the joint's longitudinal direction without enlarging the joint part.SOLUTION: A joint structure 1 of steel pipe sheet piles in this invention comprises: a male joint member 7 fitted on the outer surface along the axial direction of one main pipe 5a of adjacent main pipes; a female joint member 9 that is arranged on the outer surface along the axial direction of the other main pipe 5b of the adjacent main pipes and engages with the male joint member 7; and a filler 17 infilling the engagement part of the male joint member 7 and the female joint member 9. The joint structure is characterized by the fact that: the male joint member 7 is composed of a component with a T-like section having a web part 11 and a flange part 13; the female joint member 9 is composed of two opposing components 15a, 15b each with an L-shaped section; and the male joint member 7 is, in the joint-engaged state, fitted on the one main pipe 5a with its flange part 13 being angled 5° to 45° from the direction perpendicular to the normal line of the steel pipe sheet pile wall formed by jointing the main pipes 5a, 5b.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. 10 of Patent Document 2, for example.

[0003] Figure 10 of Patent Document 2 shows a so-called PT type joint structure, in which a joint steel pipe 1 is provided on one adjacent steel pipe sheet pile 61, and a T-shaped steel 2 is provided on the other adjacent steel pipe sheet pile 61. The stem portion 121 of the T-shaped steel 2 is inserted into the slit portion 111 of the joint steel pipe 1 to fit them together, and mortar 40 is poured into the fitting portion as a filler material.

[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 (the joint steel pipe 1 and the T-beam 2) to displace them vertically in the longitudinal direction. As a result, the mortar 40 cast 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 shear forces acting in the longitudinal direction of the joint members act on the mortar 40, 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. Therefore, there is a need to improve the adhesion between the joint members and the filler material to prevent the fitted joint members from shifting longitudinally.

[0006] Therefore, a method for increasing the adhesive strength between the joint member and the filler material is described in the aforementioned Patent Document 1. Figure 1(a) of Patent Document 1 illustrates a so-called LT-type joint structure, in which one adjacent steel pipe sheet pile main pipe 1 is provided with a male member 2 with a T-shaped cross section, and the other adjacent steel pipe sheet pile main pipe 1 is provided with two female members 4 with an L-shaped cross section. A plate-like member 5 that covers the outer surface of the main pipe 1 is incorporated into the space surrounded by the two female members 4, and a plurality of ribs 8 are provided on the surfaces of this plate-like member 5, the male member 2, and the female member 4.

[0007] According to the above joint structure, when a force is applied that shifts the joint components (male component 2, female component 4) up or down in the longitudinal direction, the cement-based filler filled in the mating portion engages with the protrusions 8, improving the shear strength and rigidity of the joint in the longitudinal direction. This allows the connected steel pipe sheet piles to function as a single unit, improving the strength of the steel pipe sheet pile foundation. [Prior art documents] [Patent documents]

[0008] [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]

[0009] As described above, by providing the joint components with protrusions (ribs 8), the strength of the joint against shear forces in the longitudinal direction is improved. However, the LT-type joint structure as disclosed in Patent Document 1 may have the following problems.

[0010] A conventional joint structure 31 of an LT type steel pipe sheet pile (hereinafter simply referred to as joint structure 31) is shown schematically in Fig. 12. Fig. 12 shows a top view of a fitting portion in a fitted joint state. In the case of the conventional joint structure 31, when the male joint member 7 is fitted to the female joint member 9, the area inside the female joint member 9 is roughly divided into three areas by the web portion 11 and flange portion 13 of the male joint member 7. Here, the area between the flange portion 13 and the main pipe 5b is referred to as area a, the area between the web portion 11 and the L-shaped member 15a is referred to as area b, and the area between the web portion 11 and the L-shaped member 15b is referred to as area c.

[0011] When the male coupling member 7 and the female coupling member 9 are fitted together, the fitting portion, i.e., areas a, b, and c, are filled with filler. However, since areas b and c have narrower spaces than area a, it is difficult to completely remove the soil and sand from within the areas and inject the filler without leaving any gaps. Therefore, even if the fitting portion is filled with a filler, it is not possible to expect sufficient adhesion of the filler to the back surface of the flange portion 13 of the male coupling member 7 or to the web portion 11 .

[0012] Therefore, essentially, only the surface of the flange portion 13 facing the main pipe 5b is considered to be an effective surface for adhering the male coupling member 7 and the filler. For this reason, in the past, protrusions were provided on at least this surface to improve the unity between the male coupling member 7 and the filler.

[0013] Here, to further enhance the integration of the male coupling member 7 and the filler, it is advisable to increase the flange width of the flange portion 13 and increase the effective adhesion area of ​​the flange portion 13 (the area of ​​the surface of the flange portion 13 on the main pipe 5b side). However, considering misalignment due to construction errors, it is necessary to provide a gap of usually about 20 mm between both side ends of the flange portion 13 and the L-shaped members 15a, 15b, and the flange width must be at most about the space width A within the female coupling member - 40 mm, which means there is a limit to how much the effective adhesion area can be increased. If the spacing between the L-shaped members 15a and 15b were increased to increase the space width A, the flange width could also be increased, but this would increase the size of the joint portion of the steel pipe sheet pile wall and the amount of filler material, which is not desirable. Therefore, a joint structure that improves the strength against shear force in the longitudinal direction of the joint without increasing the size of the joint portion of the steel pipe sheet pile wall has been desired.

[0014] 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 can improve the strength against shear forces in the longitudinal direction of the joint without increasing the size of the joint portion. [Means for solving the problem]

[0015] (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 filler material filled in the fitting portion between the male joint member and the female joint member, The male coupling member is a member having a generally T-shaped cross section and including a web portion and a flange portion, The female coupling member is made up of two members each having an L-shaped cross section, and arranged opposite each other. The male coupling member is characterized in that, in the coupling engagement state, the flange portion is attached to one of the main pipes so as to be inclined at an angle of 5° to 45° relative to the normal perpendicular to the steel pipe sheet pile wall to which the main pipe is connected.

[0016] (2) In addition, in the above (1), a stiffening member is arranged so as to connect the flange portion and one of the main pipes.

[0017] (3) Furthermore, in the above (2), the filler is filled only in the space surrounded by the female coupling member, between the flange portion of the male coupling member and the other main pipe.

[0018] (4) In the above-described (2), when the flange portion is divided into two at the joint with the web portion as a boundary, the stiffening member is disposed only on the side of the divided flange portion that is closer to the one main pipe by inclining, The filler is filled only between the flange portion of the male coupling member and the other main pipe, and between the web portion and the female coupling member, in the space surrounded by the female coupling member. [Effects of the Invention]

[0019] In the present invention, the flange portion of the male coupling member is attached to the main pipe at an angle of 5° to 45° with respect to the normal perpendicular to the steel pipe sheet pile wall, which allows the flange width to be increased without increasing the size of the coupling portion, thereby increasing the effective attachment area of ​​the flange portion and improving the strength of the coupling against shear forces in the longitudinal direction.

[0020] In addition, by tilting the flange of the male coupling member away from the normal to the steel pipe sheet pile wall, a bearing force is generated in the normal direction. Therefore, the adhesive force and bearing force between the male coupling member and the filler resist the shear force in the normal direction, further improving the shear force strength in the normal direction. From the above, the present invention can prevent the mating male and female coupling members from shifting in the longitudinal direction of the coupling and in the direction perpendicular to the normal, thereby improving the strength of steel pipe sheet pile foundations compared to conventional methods. [Brief explanation of the drawings]

[0021] [Figure 1] FIG. 2 is an explanatory diagram of a joint structure of the steel pipe sheet pile according to the first embodiment. [Figure 2] FIG. 10 is an explanatory diagram of another aspect 1 of the joint structure of the steel pipe sheet pile according to the first embodiment. [Figure 3] FIG. 10 is an explanatory diagram of another aspect 2 of the joint structure of the steel pipe sheet pile according to the first embodiment. [Figure 4] 10 is a graph (part 1) illustrating an appropriate inclination angle of a flange portion of a male coupling member. [Figure 5] Graph (Part 2) explaining the appropriate inclination angle of the flange portion of the male coupling member [Figure 6] FIG. 10 is an explanatory diagram of a joint structure of a steel pipe sheet pile according to a second embodiment. [Figure 7] FIG. 10 is an explanatory diagram of another aspect 1 of the joint structure of the steel pipe sheet pile according to the second embodiment. [Figure 8] FIG. 10 is an explanatory diagram of another aspect 2 of the joint structure of the steel pipe sheet pile according to the second embodiment. [Figure 9] FIG. 10 is an explanatory diagram of another aspect 3 of the joint structure of the steel pipe sheet pile according to the second embodiment. [Figure 10] FIG. 10 is an explanatory diagram of another aspect 4 of the joint structure of the steel pipe sheet pile according to the second embodiment. [Figure 11] FIG. 1 is a diagram showing a PT type joint structure using a male joint member of the present invention. [Figure 12] 1A and 1B are diagrams illustrating problems with a conventional LT type joint structure. DETAILED DESCRIPTION OF THE INVENTION

[0022] [Embodiment 1] A joint structure 1 for a steel pipe sheet pile according to a first embodiment of the present invention (hereinafter simply referred to as the joint structure 1) will be described with reference to FIG. 1 is a schematic diagram showing a joint structure 1 of this embodiment, illustrating 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. Note that the "normal line" used in this description 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.

[0023] The steel pipe sheet pile 3 is composed of main pipes 5a, 5b, and male joint members 7 and female joint members 9 attached to the outer surfaces of the main pipes 5a, 5b. Two adjacent steel pipe sheet piles 3 are identical, but for ease of identification, the main pipe of the steel pipe sheet pile 3 on the right side of the drawing is designated 5a, and the main pipe of the steel pipe sheet pile 3 on the left side of the drawing is designated 5b.

[0024] 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 up of two members with an L-shaped cross section (L-shaped members 15a, 15b), and is provided on the outer surface of the other main pipe 5b along the axial direction. Although not shown, a plurality of ridges are provided on the surface of flange portion 13 facing main pipe 5b and on the inner surfaces of L-shaped members 15a and 15b to increase adhesive strength with the filler. The shape, number, arrangement, etc. of the ridges are not particularly limited, but examples include ridges 8 in Patent Document 1 and protrusions 30 in Patent Document 2.

[0025] 1, the male coupling member 7 is attached to the main pipe 5a so that the flange portion 13 has a predetermined inclination with respect to the normal perpendicular direction (y direction) of the steel pipe sheet pile wall when the coupling is fitted. The inclination (inclination angle θ) of this flange portion 13 can be set arbitrarily within the range of 5° to 45°.

[0026] In the conventional joint member, as shown in Figure 12, the web portion 11 was perpendicular to the tangent of the main pipe 5a, and the flange portion 13 was perpendicular to the web portion 11, so that when the joint was fitted, the flange portion 13 was parallel to the normal perpendicular direction (y direction) of the steel pipe sheet pile wall. In contrast, the joint structure 1 of this embodiment is characterized in that the flange portion 13 is inclined relative to the normal perpendicular direction (y direction) of the steel pipe sheet pile wall when the joint is fitted, as described above. The effect of this will be described later. The reason for setting the inclination angle θ of the flange portion 13 to 5° to 45° will also be described later.

[0027] In the present invention, it is sufficient that the flange portion 13 of the male coupling member 7 has the above-mentioned inclination, and there are no limitations on the inclination of the web portion 11. Therefore, as shown in Figure 2, the web portion 11 may be attached perpendicular to the main pipe 5a, and only the flange portion 13 may be inclined.

[0028] The two L-shaped members 15a, 15b are arranged opposite each other with a predetermined gap between them, 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 two L-shaped members 15a and 15b is filled with a filler 17. Cement-based materials such as mortar and concrete are mainly used as the filler 17. It is also possible to use concrete containing geopolymers or alkali-activated materials that can reduce CO2 emissions.

[0029] As described above, by tilting the flange portion 13, it is possible to increase the flange width without increasing the spatial width A (see FIG. 12) within the female coupling member 9. Increasing the flange width increases the effective adhesion area of ​​the flange portion 13, improving the adhesion strength between the male coupling member 7 and the filler 17. This improves resistance to shear force in the z direction (a force that shifts the relative positions of the male coupling member 7 and the female coupling member 9 in the z direction) compared to the conventional example (see FIG. 12), improving the shear strength in the z direction.

[0030] Furthermore, by increasing the effective attachment area of ​​the flange portion 13, resistance to shear force in the y direction (force that displaces the relative positions of the male joint member 7 and the female joint member 9 in the y direction) also improves. Furthermore, by tilting the flange portion 13, a supporting force in the y direction is generated between the flange portion 13 and the filler 17 when a force in the y direction is applied. Therefore, the shear force in the y direction is resisted not only by the adhesive force between the male coupling member 7 and the filler 17 but also by the supporting pressure, thereby further improving the shear strength in the y direction.

[0031] The flange portion 13 may be curved in the flange width direction so as to be convex toward the web portion 11. By making the flange portion 13 curved, the effective attachment area of ​​the flange portion 13 can be further increased, and the above-mentioned improvement in the supporting force can also be expected.

[0032] In the present invention, the two L-shaped members 15a, 15b that make up the female joint member 9 do not necessarily have to be the same size, and for example, as shown in FIG. 3, members of different sizes may be combined. 3, the heights of the L-shaped members 15a and 15b are adjusted to reduce the sizes of the regions b and c in accordance with the inclination of the flange portion 13. Specifically, the length of the side extending in the x direction in the figure of the L-shaped member 15a, which is located on the side of both side ends of the flange portion 13 closer to the main pipe 5b, is made shorter than the length of the same side of the other L-shaped member 15b, thereby reducing the sizes of the regions b and c. Since the surface that is substantially effective for adhesion with the filler 17 is the surface of the flange portion 13 on the main pipe 5b side, it is not a problem if the size of areas b and c is reduced and areas b and c are not filled with the filler 17.

[0033] Next, the reason why the inclination angle θ of the flange portion 13 is set to 5° to 45° will be explained. As explained in FIG. 12, in the case of the conventional joint structure 31, when the space width within the female joint member 9 is A, the flange width of the male joint member 7 cannot be made larger than A-40 mm. In contrast, in the joint structure 1 of this embodiment, the flange width of the male joint component 7 can be made the same size as, for example, the spatial width A of the female joint component 9, while maintaining the gap of 20 mm on both sides of the flange, which is necessary to absorb construction errors.

[0034] The inclination angle (required inclination angle) of the flange portion 13 required to make the flange width the same as the space width A is shown in Fig. 4. This required inclination angle varies depending on the size of the space width A, but since the space width A is generally about 160 mm to 500 mm, Fig. 4 shows the required inclination angle when the space width A is 160 mm, 200 mm, 300 mm, 400 mm, and 500 mm.

[0035] As shown in Figure 4, for example, if the space width A is 160 mm, in order to ensure the gap (20 mm x 2) necessary to absorb construction errors while being able to place the 160 mm wide flange portion 13 within the female joint member 9, the flange portion 13 must be inclined 42° from the normal perpendicular direction (y direction) of the steel pipe sheet pile wall. Furthermore, when the space width A is 500 mm, in order to ensure the gap (20 mm x 2) necessary to absorb construction errors while being able to place the 500 mm wide flange portion 13 within the female joint member 9, the flange portion 13 must be inclined 22° from the normal perpendicular direction (y direction) of the steel pipe sheet pile wall.

[0036] From the above, when the space width A is a general size (160 mm to 500 mm), the inclination angle of the flange portion required to make the flange width the same size as the space width A is approximately 20° to 45°. From this, it is considered that if the inclination angle θ of the flange portion 13 is 20° to 45°, the effect of increasing the effective attachment area of ​​the flange portion 13 can be obtained.

[0037] As described above, in the joint structure 1 of this embodiment, the inclination of the flange portion 13 generates a bearing pressure in the y direction between the flange portion 13 and the filler material 17. The proportion of the effective bearing surface that is effective in generating this bearing pressure increases as the inclination angle of the flange portion 13 increases, as shown in Fig. 5. Here, the proportion of the effective bearing surface is the ratio of the projected width of the inclined flange portion 13 in the direction perpendicular to the normal (= flange width × sinθ) to the flange width.

[0038] Since the bearing strength Fp per unit area of ​​filler 17, such as mortar or concrete, is about 10 times the bond strength Fb, if the proportion of the effective bearing surface is 10%, a bearing force equivalent to the bond force can be obtained. As shown in Figure 5, if the inclination angle θ of flange portion 13 is 5°, the proportion of the effective bearing surface will be 10%, and the resistance to shear force in the y direction at this time will be twice that of the conventional example, including the resistance due to bond force and the resistance due to bearing force combined. From this, it can be considered that if the inclination angle θ of flange portion 13 is 5° or more, the effect of improving the bearing force in the y direction can be obtained.

[0039] From the above, the appropriate inclination angle θ of the flange portion 13 in the present invention, that is, the inclination with respect to the direction perpendicular to the normal line of the steel pipe sheet pile wall, is 5° to 45°, and more preferably 20° to 45°.

[0040] As described above, according to the joint structure 1 of this embodiment, by tilting the flange portion 13 of the male joint member 7 from the direction perpendicular to the normal to the steel pipe sheet pile wall, the effective attachment area of ​​the flange portion 13 can be increased without increasing the installation spacing of the L-shaped members 15a, 15b that constitute the female joint member 9. This improves the adhesive strength between the male joint member 7 and the filler material 17, thereby improving the strength against shear force in the joint longitudinal direction (z direction) without increasing the size of the joint portion of the steel pipe sheet pile wall.

[0041] Furthermore, by tilting the flange portion 13, a bearing pressure is generated between the male coupling member 7 and the filler material 17 in the direction perpendicular to the normal to the steel pipe sheet pile wall (y direction). Therefore, not only the adhesive force between the flange portion 13 and the filler material 17 but also the bearing pressure is added against the shear force in the y direction, and further strength improvement can be expected.

[0042] [Embodiment 2] As explained in the first embodiment, by tilting the flange portion 13 of the male coupling member 7, the effective attachment area of ​​the flange portion 13 can be increased, improving the anchoring force between the male coupling member 7 and the filler material 17. This increases the unity between the male coupling member 7 and the filler material 17 and improves the strength of the steel pipe sheet pile foundation, but on the other hand, the rigidity and bearing capacity of the web portion 11 of the male coupling member 7 may become a weak point. Therefore, in this embodiment, an example in which the web portion 11 of the male joint member 7 is stiffened will be described.

[0043] Fig. 6 is a schematic diagram showing a joint structure 19 of a steel pipe sheet pile according to this embodiment (hereinafter simply referred to as the joint structure 19). In Fig. 6, the same components as those in Fig. 1 are denoted by the same reference numerals, and the description thereof will be omitted. 6, the joint structure 19 of this embodiment includes a stiffening member 21 arranged to connect the flange portion 13 of the male joint member 7 and the main pipe 5a. By providing such a stiffening member 21, the stiffening member 21 stiffens the web portion 11, making it possible to prevent deformation of the web portion 11 when an external force such as an earthquake acts on it. The stiffening members 21 may be attached continuously or discretely along the axial direction of the main pipe 5a.

[0044] Furthermore, when the flange portion 13 is divided into two at the joint with the web portion 11, the stiffening members 21 in Fig. 6 are arranged on the side of the divided flange portion 13 that is closer to the main pipe 5a due to the inclination (below the web portion 11 in the figure), but the arrangement of the stiffening members 21 is not limited to this. For example, the stiffening members 21 may be arranged on the side away from the main pipe 5a (above the web portion 11 in the figure), or stiffening members 21 may be arranged on both sides of the web portion 11. However, when the stiffening members 21 are arranged as in the example of Fig. 6, there is an advantage when filling the filler 17, which will be described later.

[0045] Furthermore, although FIG. 6 shows an example in which the entire space surrounded by the female coupling member 9 is filled with the filler 17, in the present invention, it is not necessarily necessary to fill the entire space surrounded by the female coupling member 9, i.e., all of the regions a, b, and c, with the filler 17. As mentioned above, the area of ​​the male coupling member 7 that is substantially effective for adhesion of the filler 17 is the surface of the flange portion 13 facing the main pipe 5b, so the filler 17 may be filled only in region a, as shown in Figure 7. In this way, even if the filler 17 is filled only in region a, i.e., between the flange portion 13 of the male coupling member 7 and the main pipe 5b, the effect of increasing the effective adhesion area of ​​the flange portion 13 according to the present invention can be sufficiently obtained.

[0046] Furthermore, in this case, when carrying out construction, it is sufficient to place an injection pipe in area a and inject filler 17, filling only area a with filler 17, and there is no need to place an injection pipe in area b or c and further inject filler 17. As mentioned above, areas b and c have narrower spaces than area a, making it difficult to completely remove soil and sand from these areas, so eliminating the need to inject filler into areas b and c improves workability. Here, "filled" means a state in which the filler material is injected into the target area from an injection tube, filling the area with the filler material, and is different from a state in which the filler material leaks from the target area into an adjacent area and enters the adjacent area.

[0047] In addition, since the space in region b is larger than in the conventional example (see FIG. 12) due to the inclination of flange portion 13, it is easier to remove soil and sand than in the conventional example, and it is also easier to fill with filler 17. Therefore, as shown in FIG. 8, it is also possible to use a configuration in which regions a and b are filled with filler 17. In the embodiment of FIG. 8, the male coupling member 7 is more tightly constrained than in the embodiment of FIG. 7, and therefore it is expected that the fixation of the male coupling member 7 and the filler 17 will be further improved.

[0048] Furthermore, when filling region b with filler 17, if stiffening members 21 are present on the region b side, it will be difficult to remove soil and sand and to inject filler 17, so it is advisable to arrange stiffening members 21 only on the region c side as shown in Figure 8. Specifically, when flange portion 13 is divided into two at the joint with web portion 11, it is desirable to arrange stiffening members 21 only on the side of flange portion 13 that is tilted and approaches main pipe 5a. Furthermore, a water-stop material may be placed in region a or region b, or both, in Figure 8. By placing, for example, a gel-filled water-stop material in these areas, it is possible to prevent the formation of water paths and prevent water leakage during and after construction.

[0049] In another embodiment, as shown in Figures 9 and 10, a protruding steel plate 23 or a deformed steel bar 25 having surface protrusions may be provided at the position where the main pipe 5b on the female coupling member 9 side and the filler material 17 contact. By providing the protruding steel plate 23 or the deformed steel bar 25, when a shear force in the z direction acts, the protrusions formed on the surface of the protruding steel plate 23 or the deformed steel bar 25 resist the shear force in the z direction, improving the anchoring force of the female joint member 9 and the filler material 17. The protruding steel plate 23 in FIG. 9 and the deformed steel bar 25 in FIG. 10 are not limited to this embodiment, and may be applied to the joint structure 1 in embodiment 1, in which case the same effects as those described above can be expected.

[0050] As described above, according to the joint structure 19 of this embodiment, the stiffening member 21 is arranged to connect the flange portion 13 of the male joint member 7 and the main pipe 5a, so that the stiffening member 21 stiffens the web portion 11 and prevents the web portion 11 from deforming when an external force such as an earthquake acts on it. Furthermore, by stiffening the web portion 11, the rigidity of the entire male coupling member 7 is improved, so it is not necessary to fill the region b or region c with the filler 17, and workability is improved.

[0051] The joint structures 1 and 19 illustrated in the first and second embodiments are both LT-type joint structures, but the male joint member and stiffening member of the present invention can also be applied to a PT-type joint structure 27 as shown in Figures 11(a) and 11(b). In the case of the PT type joint structure 27, a steel pipe for joints is used for the female joint member 29, so no matter what inclination angle is given to the flange portion 13 of the male joint member 7, the flange width cannot be increased, but it is possible to obtain a support force that resists the shear force in the y direction. Therefore, if the male coupling member and stiffening member of the present invention are applied to a PT type coupling structure, such as the coupling structure 27 in Figures 11(a) and 11(b), a certain effect can be obtained in improving the strength of the coupling portion. [Explanation of symbols]

[0052] 1 (Steel pipe sheet pile) joint structure (embodiment 1) 3 Steel pipe sheet piles 5a, 5b main 7 Male coupling member 9 Female coupling member 11 Web Department 13 Flange 15a, 15b L-shaped members 17 Filling material 19 (Steel pipe sheet pile) joint structure (embodiment 2) 21 Stiffening member 23 Projected steel plate 25 Deformed steel bars 27 (Steel pipe sheet pile) joint structure (PT type) 29 Female joint member (PT type) 31 (Steel pipe sheet pile) joint structure (conventional example)

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 filler 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, The female coupling member is made up of two members each having an L-shaped cross section, and arranged opposite each other. A steel pipe sheet pile joint structure characterized in that, when the joint is fitted, the male joint member is attached to one of the main pipes so that the flange portion is inclined at an angle of 5° to 45° relative to the normal perpendicular to the steel pipe sheet pile wall to which the main pipe is connected.

2. 2. The joint structure of a steel pipe sheet pile according to claim 1, further comprising a stiffening member arranged to connect the flange portion and the one of the main pipes.

3. 3. The steel pipe sheet pile joint structure according to claim 2, wherein the filler is filled only in the space surrounded by the female joint member between the flange portion of the male joint member and the other main pipe.

4. When the flange portion is divided into two at the joint with the web portion as a boundary, the stiffening member is disposed only on the side of the divided flange portion that is closer to the one main pipe by being tilted, 3. A steel pipe sheet pile joint structure according to claim 2, characterized in that the filler is filled only between the flange portion of the male joint member and the other main pipe, and between the web portion and the female joint member, in the space surrounded by the female joint member.

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