JP2000355933A - Steel pipe sheet pile and connection structure therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure a required shear strength in a joint at a construction site by fitting a circular steel pipe constituting the joint member setting the axis in parallel to an external face of the steel sheet pipe pile body and forming a slit axially stretching in the circular steel pipe and forming a plurality of through holes in specified positions of the circular steel pipe. SOLUTION: A circular steel pipe 2 having a smaller diameter than a steel pipe sheet pile body 1 is welded to the external face of the steel pipe sheet pile body 1. A fitting slit 2a is formed along the axial direction of the pipe in the circular steel pipe 2. A plurality of through holes 7 are formed on the whole face, when the inside face of the longer side 2b of the arc length in the arcs 2b, 2c forming between slits 2a of the fitting part 5 to the sheet pile pipe body 1 of the circular steel pipe 2 turns to the steel pipe sheet pile body side 1, that is, in the fitting part through slits 2a in the other circular steel pipe 2. In this way, even if the fitting space B of mutual steel pipes of P-Ptype joint member gets extremely narrow, they can be securely cleaned and filled with mortar.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steel pipe sheet pile having a joint structure and a connecting structure between steel pipe sheet piles, and more particularly to a steel pipe sheet pile and a connecting structure for a steel pipe sheet pile which are effective for a large-scale steel pipe sheet pile foundation. .

[0002]

2. Description of the Related Art Today, steel sheet pile foundations are indispensable as one of the bridge foundations. For example, as shown in FIG. 7, the steel pipe sheet pile foundation is configured such that a plurality of steel pipe sheet piles 50 are formed into a closed shape such as a circular shape, an oval shape, and a rectangular shape while fitting and connecting joint members of adjacent steel pipe sheet piles 50 to each other. It is constructed by pouring into the ground so as to form a top slab concrete 51 in the closed internal space.

Conventionally, as a joint member of a steel pipe sheet pile foundation,
As shown in FIG. 8, a PP type is generally used. This PP type joint member is provided with a slit 53 a along a pipe axis direction in a circular steel pipe 53 having a smaller diameter than the steel pipe sheet pile main pipe 52.
Which is attached to the outer surface of the steel sheet pile main pipe 52. Then, in the construction, for the adjacent steel pipe sheet pile 50, after being driven into the ground while fitting the circular steel pipes 53 through the slits 53a, excavating and discharging the earth and sand in the circular steel pipes 53, After cleaning the inner surface of the circular steel pipe 53, the space is filled with mortar 54 to connect the steel pipe sheet piles 50 together.

Generally, a circular steel pipe 53 used for a PP joint member has an outer diameter of 165.2 mm and a plate thickness of 11 mm (or 9 m).
m), the one with no irregularities such as protrusions on the inner and outer surfaces is used. On the other hand, the mortar 54 to be filled has a compressive strength of 2
The thing of about 00kgf / cm ² is used. Here, when a horizontal external force acts on the steel sheet pile foundation, a vertical shear force acts on the joint portion. If this shearing force is larger than the shear strength of the joint, the shear deformation of the joint rapidly increases, and the degree of reduction in the bending rigidity of the entire steel sheet pile foundation also increases.

As measures for increasing the bending rigidity of the entire foundation, it is conceivable to improve the shear strength of the joint portion or to increase the number of sheet piles 50. But,
In the case of increasing the bending rigidity of the entire foundation in a large-scale bridge foundation on which a large external force acts, if a method of increasing the number of the steel pipe sheet piles 50 is adopted, the scale of the foundation becomes excessively large, resulting in an uneconomical foundation. . Therefore, in order to increase the bending stiffness within a range where the scale of the foundation does not become excessive, it is necessary to use a joint member having a large shear strength.

[0006] The shear strength of the PP joint member is as follows.
It depends on the adhesive strength between the surface of the circular steel pipe 53 and the mortar 54, which is the adhesive strength and frictional force. However, the conventional P
In the case of a -P type joint member, this adhesion is easily broken, so that in order to construct an economical large-scale bridge foundation with a steel pipe sheet pile foundation, a joint member having a greater shear strength than in the past has been required. Incidentally, the shear strength of the conventional PP joint member was about 25 to 35 tf / m per unit joint member length.

[0007] As a measure for improving the shear strength of the above-mentioned joint, for example, reference 1 (Katayama et al .: Recent research and development in steel pipe sheet pile foundation method, foundation work, November 1993) and reference 2
(Katayama et al .: Experimental study on high-strength joints for steel sheet pile foundations, 49th Annual Scientific Meeting of the Japan Society of Civil Engineers, September 1994). The first measure described in these documents is to provide a large number of protrusions on the inner surface of the circular steel pipe 53 of the PP type joint member. It increases the adhesive strength. By the way, as a result of conducting an experiment on a circular steel pipe 53 having an outer surface with a projection of 165.2 mm and a plate thickness of 9 mm and a mortar 54 having a compressive strength of 240 kgf / cm ² , the unit joint member length 105tf per
/ M 2, and it was confirmed that the shear strength greatly increased.

A second measure described in the above-mentioned document is to increase the diameter of the circular steel pipe 53 of the PP type joint member. The diameter of the circular steel pipe 53 and the mortar 54 are increased by increasing the diameter. And increase the shear strength of the joint. By the way, as a result of conducting an experiment on a steel pipe 53 having an outer diameter of 216.3 mm and a plate thickness of 11 mm (without projections and other irregularities) and a mortar having a compressive strength of 240 kgf / cm ² , a unit joint member was obtained. 44 per head
Shear strength is tf / m, and shear strength is increasing.

Further, it can be easily inferred that the shear strength is further improved by combining the above two measures. When the present inventor confirmed the effects of these two measures in a laboratory experiment, a large shear strength was obtained by combining the two measures described above. One embodiment is shown in FIG. In this example, the steel pipe thickness is 12 mm, the material yield strength of the steel pipe is 2400 kgf / cm ² , the compressive strength of the mortar 54 (filler) is 200 kgf / cm ² ,
In this example, the shear strength of the joint member was evaluated using only the outer diameter of No. 3 as a parameter. In the experimental case, the outer diameter of the steel pipe was 165.
2mm, 216.3mm, 241.8mm, 318.5mm, 355.6mm, 406.4
mm. It was confirmed that a large shear strength was obtained by using a steel pipe having a projection on the inner surface and increasing the diameter of the steel pipe as compared with the steel pipe of the conventional PP joint member.

[0010]

Here, the circular steel pipe 53 is used.
Investigation of the situation of adhesion failure between the mortar 54 and
Of the two circular steel pipes 53 connected by fitting, the inner surface of the long circular arc side 53b of the two circular arcs 53b, 53c extending in the circumferential direction from the attachment portion to the steel pipe sheet pile main pipe 52 to the slit position faces each other. A space B surrounded by the fitting portion 55, that is, a space surrounded by the fitting portions 55 fitted to each other in the other circular steel pipe 53 through the slit 53a (hereinafter, may be referred to as a fitting space B). The maximum proof stress was determined by the lack of adhesion (see FIG. 10). Therefore,
In order to exert the large shear strength confirmed in the above-mentioned laboratory experiment, in this fitting space B, a mortar 54 having a predetermined strength is used without any gap until the projection on the inner surface of the circular steel pipe 53 and the mortar 54 engage. We have found that it is the most important to ensure filling.

That is, in order to obtain a large shear strength on site by adopting the above two measures, the fitting space B
The mortar 5 with no gap against the inner surface of the circular steel pipe 53
4 must be applied. However, in the case where the steel pipe sheet pile 50 is driven at an actual site, the tip of the sheet pile is not driven vertically due to the influence of the difference in the hardness of the ground and the like, and the steel sheet pile 50 is separated from the adjacent preceding steel pipe sheet pile 50 that has been driven. The tip of the steel pipe sheet pile 50 during driving may advance in the direction. At this time, since the circular steel pipes 53 are driven while being fitted to each other, the position of the steel pipe sheet pile 50 does not largely shift, but the circular steel pipe 5 having a slit to be fitted and connected.
When the three are pulled away from each other, deformation such as twisting occurs in the circular steel pipe 53 so that the slit 53a is opened. Then, as shown in FIG. 11, in each circular steel pipe 53, a side 53 b having a longer arc length out of two arcs extending in a circumferential direction from a mounting portion to the steel pipe sheet pile main pipe 52 to a position of the slit 53 a is expanded. The fitting space B formed between the fitting portions 55 on the arc length side is the steel pipe sheet pile 5.
0 becomes narrower than the case where it is driven vertically. This tendency becomes more remarkable when the plate thickness of the circular steel pipe 53 is the same, as the diameter is larger, that is, as the diameter of the circular steel pipe 53 is increased in order to improve the shear strength of the joint based on the second measure. .

When the fitting space B becomes excessively narrow, a pipe for jetting a water jet for washing or a pipe for injecting a filler such as mortar into the fitting space B has a predetermined size. It is difficult to sink to the depth.
Then, it is not possible to sufficiently remove the earth and sand attached to the protruding surfaces on the inner surface of the fitting portion 55 of the circular steel pipe 53 forming the fitting space B and the recesses between the protrusions, or to make the mortar and the protrusion on the inner surface of the fitting portion 55 more difficult. There is no gap to the point where the mortar 54 is sufficiently engaged with the mortar 54 having a predetermined strength.

That is, even if the two measures for increasing the shear strength as described above are combined or used alone to obtain a large shear strength, the fitting portion for determining the maximum strength is actually used at the site. About 55
There is no gap until the projections on the inner surface of the steel pipe 53 and the mortar 54 mesh with each other, and the mortar 54 having the predetermined strength cannot be reliably filled. Shear strength cannot be ensured stably at actual sites.

That is, there is a problem that a large shear strength as confirmed by an experiment cannot be reliably exerted on the joint portion at the site. The present invention has been made in view of such a point, and even when the fitting space may be excessively narrow when the circular steel pipes of the PP joint member are connected by fitting, even if the fitting space is excessively narrowed, It is an object of the present invention to provide a steel pipe sheet pile capable of ensuring a predetermined desired shear strength for a joint portion and a steel pipe sheet pile connection structure suitable for a large-scale steel pipe sheet pile foundation.

[0015]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, a first aspect of the present invention is to provide a circular pipe for forming a joint member with an outer surface of a steel sheet pile main pipe in parallel with the steel pipe sheet pile main axis. In a steel pipe sheet pile having a steel pipe attached thereto and a slit extending in an axial direction formed in the circular steel pipe, two circular arcs extending in a circumferential direction from a portion of the circular steel pipe attached to the steel pipe sheet pile main pipe to a slit position. A steel pipe sheet pile characterized by having a plurality of through-holes at least at the position where the inner surface faces the steel pipe sheet pile main pipe side with respect to the arc part having the longer arc length.

Here, "the position where the inner surface of the arc portion having the longer arc length faces the steel pipe sheet pile main pipe side" means that when the circular steel pipes of the adjacent steel pipe sheet piles are fitted together, Refers to a fitting part fitted into a circular steel pipe through a slit. Next, the invention described in claim 2 corresponds to claim 1
In contrast to the configuration described in (1), irregularities are provided on the inner surface of the circular steel pipe.

Next, according to a third aspect of the present invention, a circular steel pipe forming a joint member is attached to an outer surface of the steel sheet pile main pipe with the axis parallel to the steel pipe sheet main pipe, and the circular steel pipe is attached to the circular steel pipe. Is a connecting structure of steel pipe sheet piles formed with a slit extending in the axial direction, wherein at least one of the adjacent steel pipe sheet piles is the steel pipe sheet pile according to any one of claims 1 and 2, and the adjacent steel pipes It is another object of the present invention to provide a steel pipe sheet pile connecting structure in which the circular steel pipes of the sheet pile are fitted together through the slits and the circular steel pipe is filled with a filler.

According to the present invention, even when the fitting space formed between the fitting portions of the two circular steel pipes to be fitted may become excessively narrow, the through hole is formed in the fitting portion. Since it is open, washing in the fitting space from the space located on both sides of the fitting space and ensuring a relatively large space, that is, from the outer surface side of the fitting part through the through hole, It is possible to reliably perform the filling, and it is possible to fill the space with a filler such as mortar without any gap.

Further, as described above, the adhesion strength between the inner surface of the fitting part of the circular steel pipe and the filler determines the maximum proof stress of the joint portion. The adhesive strength between the inner surface of the fitting portion and the filler is improved. The shape of the opening of the through hole is not limited at all.

[0020]

Next, embodiments of the present invention will be described with reference to the drawings. First, a steel pipe sheet pile A of the present embodiment will be described. As shown in FIG.
A circular steel pipe 2 smaller in diameter than the steel sheet pile main pipe 1 is attached to the outer surface of the steel pipe 1 by flare welding. In this circular steel pipe 2,
A slit 2a for fitting is provided along the tube axis direction. In FIG. 1, only one circular steel pipe 2 as a joint member is shown, but it is also present on the opposite side.

As shown in FIG. 2, a plurality of checker-like projections 4 are provided on the entire inner surface of the circular steel pipe 2 so that irregularities are formed on the inner surface. The adhesion strength with the mortar (filler) is improved. Further, of the circular arc pipe 2, the inner surface of the circular arc portion of the long circular arc side 2 b of the two circular arcs 2 b, 2 c formed between the attachment part 5 to the steel pipe sheet pile main pipe 1 and the slit 2 a has a steel pipe sheet pile. A plurality of through-holes 7 are opened over the entire surface at a position 6 facing the main pipe side 1.

As shown in FIG. 3, when the inner surface faces the steel pipe sheet pile main pipe side 1 when the circular steel pipes 2 of the adjacent steel pipe sheet piles A are fitted to each other, a slit is formed in the other circular steel pipe 2. Part fitted through 2a (hereinafter referred to as fitting part 6)
It is. As in the prior art, for each steel sheet pile A, as shown in FIG. 3, the circular steel pipe 2 is fitted to the circular steel pipe 2 of the adjacent steel pipe sheet pile A through the slit 2a while being fitted. Is poured into the ground, and subsequently, the earth and sand in the internal space at the joint is excavated, discharged, and washed, and then the space is filled with mortar to connect the steel pipe sheet piles A to each other. This is performed along the position of the closed shape intended. In addition, top slab concrete is constructed in the constructed internal space of the closed shape to make a steel pipe sheet pile foundation.

Here, the inside of the two circular steel pipes 2 connected by fitting is divided into three chambers of a fitting space B and internal spaces C on both sides thereof by a pair of fitting portions 6. Conventionally, as shown in FIG. 4, the work of cleaning and fitting the mortar in the fitted circular steel pipe is performed by individually inserting pipes 8 into the three spaces B and C, respectively. There is a need.

On the other hand, in the present embodiment, the fitting space B is not inserted into the internal space C on both sides without inserting a pipe for jetting a water jet and a pipe for injecting a filler. Only the washing and pouring pipes 8 may be laid down to perform the washing and mortar filling operations. The high-pressure water spouted from the cleaning pipe inserted into each internal space C and the mortar injected from the injection pipe are also jetted into the fitting space B through the through hole 7 opened in the fitting portion 6. Alternatively, the washing and the filling of the mortar with respect to the internal space C on both sides are performed, so that the washing and the filling of the mortar in the fitting space B are also reliably performed.

Therefore, the fitting space B becomes excessively narrow due to the unevenness of the hardness or the like of the ground on which the sheet pile A is cast, and only the washing pipe or the like is sufficiently settled in the fitting space B. Even if the cross section cannot be secured, the fitting space B can be reliably washed, and the soil attached to the inner surface of the fitting portion 6, particularly the soil attached to the concave portion or the convex portion, is reliably removed. Is done. Then, the mortar can be reliably filled in the fitting space B. In addition, since the inner surface of the fitting portion 6 is reliably and sufficiently cleaned as described above, the mortar adheres to a position where the mortar meshes with the unevenness of the inner surface of the fitting portion 6 without any gap.

Conversely, as the fitting space B becomes excessively narrow,
The washing and filling of the mortar from the internal spaces C on both sides are reliably performed. When the fitting space B is sufficiently large, the pipes may be individually inserted into the fitting space B to perform the cleaning and filling operations as in the related art. In this way, even if the fitting space B that determines the maximum shear strength of the joint portion becomes small, the mortar is reliably filled in the fitting space B, and the mortar is securely filled on the entire inner surface of the fitting portion 6. Adhere to.

As described above, by using the steel pipe sheet pile A according to the present invention, it is possible to use the large-diameter circular steel pipe 2 and to provide the inner surface of the circular steel pipe 2 with irregularities, thereby improving the shear strength confirmed in a laboratory experiment. The same large shear strength can be reliably obtained even at sites where the ground is uneven. That is, when the steel pipe sheet pile A having the above-described joint structure is used, the bonding strength between the filled mortar and the filled mortar can be reliably improved at the site, and the joint of the steel pipe sheet pile A can be improved. The shear strength of the portion can be surely significantly improved as compared with the conventional PP joint member.

As a result, the bending stiffness of the entire steel pipe sheet pile foundation can be greatly increased as compared with the prior art.
Steel pipe sheet pile foundations can now be applied to large-scale bridge foundations that were previously difficult to apply. Here, the form of the projection 4 provided on the inner surface of the circular steel pipe 2 is not limited to the checker-like form. For example, as shown in FIG. FIG. 6 which is a diagram
Alternatively, a pattern close to a plurality of rings perpendicular to the tube axis direction as shown in FIG.

Although the mortar is exemplified as the filler, the filler is not limited to the mortar. For example, even a concrete or the like may be used as long as it has a predetermined compressive strength. In the above embodiment,
Although the case where the unevenness is provided on the inner surface of the circular steel pipe 2 is described as an example, the unevenness may not be formed on the inner surface of the circular steel pipe 2. However, the effect of the present invention is most effectively exerted in the case where irregularities on which earth and sand are apt to adhere are provided.

Further, in the above embodiment, the through holes 7 are provided in both the circular steel pipes 2 of the steel pipe sheet piles A to be fitted and connected. However, the internal space C is formed only when the fitting space B becomes excessively narrow. When the fitting / closing space B is to be washed and filled from the side, the through-hole 7 may be provided only in the one adjacent circular steel pipe 2. Also in this case, it is possible to obtain a greater shear strength than a conventional PP joint. However,
When the through hole 7 is provided only in one of the circular steel pipes 2, it is preferable to provide the through holes in both the circular steel pipes 2 since the washing of the earth and sand in the fitting space B tends to be insufficient.

[0031]

EXAMPLE After a steel pipe sheet pile A having a length of 10 m was cast on an actual ground, mortar was filled into a circular steel pipe 2 of a joint portion.
After the mortar was hardened, a part of the joint was cut out and the shear strength of the joint was examined indoors. The steel pipe sheet pile A used in the experiment had an outer diameter of 1000 mm and a thickness of 16 mm. The circular steel pipe 2 used had an outer diameter of 318.5 mm and a thickness of 12 mm. The mortar used had a compressive strength of 200 kgf / cm ^2. did.

Further, other conditions, the presence or absence of a through hole 7 in the fitting portion, the position for inserting the pipe 8 for jetting a water jet and the pipe 8 for injecting a filler,
Experiments were carried out with the presence or absence of the protrusion 4 being changed as shown in Table 1. Table 1 shows the experimental cases and their effects.

[0033]

[Table 1]

When a three-piece case 1 having a circular steel pipe 2 having a projection 4 on the inner surface and having no through hole 7 was constructed,
As for the body, various pipes 8 could be sunk to a predetermined depth and filled with mortar, but for the remaining one body, the pipe 8
Could be sunk only to about 2/3 of the target depth. This was because the arc 2b of the circular steel pipe 2 was excessively deformed and the fitting space B became too narrow.

The remaining two cases (Case 1-1, Case 1) in which the mortar in Case 1 was able to be driven to a predetermined depth.
The joint strength of -3) is 265tf / m and 232tf / m, respectively.
Significantly greater shear strength was obtained as compared to the results of laboratory tests of conventional PP joint members of about 25 to 35 tf / m. However, considering the case where the mortar cannot be filled at all with the remaining one body (case 1-2), that is, the case where the shear strength is hardly expected, the shear strength is hardly expected on a part of the foundation. There is a possibility that a division may occur, and if the joint of this case (case 1) is applied to actual construction, the reliability is lacking.

On the other hand, a circular steel pipe 2 having a projection 4 on the inner surface
In addition to providing a through hole 7, one case 2 in which various pipes 8 are settled in a fitting space B and internal spaces C on both sides thereof, and a circular steel pipe 2 having a projection 4 on the inner surface.
In addition to providing the through hole 7 in the fitting portion 6 and connecting the various pipes 8 not to the fitting space B but to the internal spaces C on both sides thereof,
When three cases 3 were sunk only in the case, various pipes 8 could be sunk to a predetermined depth in any case,
The mortar could be filled. The joint proof stress of each case (Case 2 and Case 3) was 149 tf / m for Case 2, 138 tf / m, 122 tf / m and 165 tf / m for Case 3.

Since all three cases 3 had a large shear strength equivalent to that of the case 2, the water jets were inserted not into the fitting space B but into the internal spaces C on both sides of the fitting space B. The high-pressure water jetted from the pipe 8 and the pipe 8 for injecting the filler, and the filler are:
It reaches the fitting space B through the through hole 7, and it is understood that the fitting space B is surely filled with the mortar.

The shear strength of the case 3 is equal to that of the case 1.
Although it is small in comparison with the conventional PP-type joint member, it is possible to obtain a remarkably large shear strength compared with about 25 to 35 tf / m in the laboratory test result of the conventional PP-type joint member, and the construction reliability is higher than that of the case 1. Considering this, it can be determined that the joint structure of the case 3 according to the present invention is excellent.

Each of the case 4 and the case 5 is a circular steel pipe 2 having no projection 4 on its inner surface, and a case in which a through hole 7 is provided.
An experiment was conducted on a case where the through-hole 7 was not provided. The joint proof stress of each case (Case 4 and Case 5) was 78 tf / m for Case 4 and 45 tf / m for Case 5 respectively. It can be seen that even when the circular steel pipe 2 without the projections 4 is used, the provision of the through holes 7 improves the adhesive strength, and as a result, a somewhat large shear strength can be obtained.

That is, although the conventional PP type joint has insufficient shear strength, the present invention is not applied to a medium-sized bridge foundation which does not need to use a PP type joint using the circular steel pipe 2 having the projection 4. It can be seen that the circular steel pipe 2 without the projections 4 shown in the case 5 is also effective.

[0041]

As described above, when the present invention is adopted, the fitting space for determining the maximum strength of the shear strength of the joint portion of the steel pipe sheet pile can be reliably cleaned and filled with the filler such as mortar. In addition, since the filler can be sufficiently adhered to the entire inner surface of the fitting portion of the circular steel pipe surrounding the fitting space, the joint portion of the steel pipe sheet pile can be stably provided with a predetermined or more shear strength at the site. be able to.

Therefore, in the case where irregularities are provided on the inner surface of the circular steel pipe in order to obtain a large shear strength, since the earth and sand on the inner surface of the fitting portion can be reliably removed, a large shear strength can be reliably obtained at the site. That is, by using the steel pipe sheet pile according to the second aspect, it is possible to ensure that the joint portion has a large shear strength at the site.

Further, if the diameter of the circular steel pipe is increased to obtain a large shear strength, the circular steel pipe is likely to be deformed when the steel pipe sheet pile is deformed, and as a result, the fitting space may become excessively narrow. However, also in this case, the effect of improving the shear strength by enlarging the diameter of the circular steel pipe can be reliably obtained on site. Thus, when the present invention is adopted, it is a method of improving the shear strength of the joint portion.
Even if the method of providing irregularities on the inner surface of the circular steel pipe and the method of increasing the diameter of the steel pipe are used alone or in combination,
In the field, it is possible to reliably improve the shear strength.

Further, since the cleaning operation and the filling operation of the filling material in the two circular steel pipes which are fitted and connected only need to be performed in the spaces on both sides of the fitting space, the cleaning operation and the filling operation can be reduced. It becomes possible. By adopting the steel pipe sheet pile connecting structure according to the third aspect, the bending rigidity of the entire steel pipe sheet pile foundation can be greatly increased as compared with the conventional steel pipe sheet pile foundation. There is also an effect that a steel pipe sheet pile foundation can be applied to a bridge foundation.

[Brief description of the drawings]

FIG. 1 is a view showing a steel pipe sheet pile according to an embodiment based on the present invention, wherein (a) is a plan view and (b) is a side view.

FIG. 2 is a diagram showing an example of a concavo-convex pattern formed on an inner surface of a circular steel pipe according to an embodiment based on the present invention.

FIG. 3 is a plan view showing a through-hole and the like according to the embodiment based on the present invention.

FIG. 4 is a plan view showing a conventional pipe insertion position.

FIG. 5 is a diagram showing another example of the concavo-convex pattern formed on the inner surface of the circular steel pipe according to the embodiment based on the present invention.

FIG. 6 is a diagram showing another example of the concavo-convex pattern formed on the inner surface of the circular steel pipe according to the embodiment based on the present invention.

FIG. 7 is a view showing an example of a steel pipe sheet pile foundation.

FIG. 8 is a view showing connection of a conventional steel pipe sheet pile.

FIG. 9 is a diagram showing the relationship between the outer diameter of a steel pipe and the shear strength.

FIG. 10 is a view for explaining a portion for determining a maximum proof stress in a joint portion.

FIG. 11 is a diagram for explaining a conventional problem.

[Explanation of symbols]

 Reference Signs List A steel pipe sheet pile B fitting space C internal space 1 steel pipe sheet pile main pipe 2 circular steel pipe 2a slit 2b long side arc 2c short side arc 4 protrusion 7 through hole 8 pipe

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Shoji Hashimoto 2-3-2 Uchisaiwai-cho, Chiyoda-ku, Tokyo Inside Kawasaki Steel Corporation (72) Inventor Hiroshi Kazama 1-2-3 Shibaura, Minato-ku, Tokyo Shimizu Construction Co., Ltd. F-term (reference) 2D049 FB03 FB14 FC03 FD04

Claims (3)

[Claims] 1. A circular steel pipe constituting a joint member with an axis parallel to the steel sheet pile main pipe attached to an outer surface of the steel sheet pile main pipe, and a slit extending in an axial direction is formed in the circular steel pipe. In the steel pipe sheet pile, at least an inner surface of the steel pipe sheet pile of at least the inner surface of the circular arc part of the circular steel pipe having a longer arc length out of two circular arcs extending in the circumferential direction from the attachment portion to the steel pipe sheet pile main pipe to the slit position. A steel pipe sheet pile comprising a plurality of through holes provided at a position facing the main pipe. 2. The steel pipe sheet pile according to claim 1, wherein irregularities are provided on an inner surface of the circular steel pipe. 3. A circular steel pipe constituting a joint member with an axis parallel to the steel sheet pile main pipe attached to an outer surface of the steel sheet pile main pipe, and a slit extending in an axial direction is formed in the circular steel pipe. A connection structure of steel pipe sheet piles, wherein at least one of the adjacent steel pipe sheet piles is the steel pipe sheet pile according to any one of claims 1 or 2, and the circular steel pipes of the adjacent steel pipe sheet piles have the slits. A connection structure for steel pipe sheet piles, wherein the steel pipe sheet piles are fitted with each other via a filler material and filled in the circular steel pipe.