JP7702277B2 - Manufacturing method of steel sheet pile - Google Patents

Description

The present invention relates to a method for manufacturing steel sheet piles.

Steel sheet piles are known that are driven into the ground by fitting their joints together. Steel sheet piles are made of strip-shaped steel plates and are widely used as retaining walls when constructing underground structures and as temporary partitions when constructing port and water facilities (see, for example, Patent Document 1).

JP 2002-201633 A

Generally, steel sheet piles are made by winding a strip of steel plate into a coil roll, which is then unwound by an uncoiler, and the unwound steel plate passes through a roll forming machine to be shaped into a predetermined cross-sectional shape. As shown in FIG. 12, the steel plate 1000 formed by the roll forming machine has a web portion 1100, a flange portion 1200, and a joint portion 1300. The joint portion 1300 is formed by rolling and folding back the end of the steel plate in the width direction W.

The steel plate 1000 that has been through the roll forming process to manufacture the steel sheet pile is cut to a specified length. In FIG. 13, which shows the cutting of the steel plate 1000, the lower blade member 310 is inserted into the joint portion 1300 to support the steel plate 1000 from below so as to prevent the joint portion 1300 from being crushed. Next, the upper blade member 320 is brought close to the steel plate 1000 in an approach direction A toward the steel plate 1000 from the side opposite the lower blade member 310, to cut the steel plate 1000 in the width direction W.

The joint portion 1300 is folded back by roll forming, forming a portion 1400 where the plate materials overlap in plan view. The lower blade member 310 is pressed from above by the steel plate 1000 being cut by the upper blade member 320. As a result, excessive load is applied to the neck portion 313 of the lower blade member 310 inserted into the joint portion 1300 during cutting, and there is concern that this may shorten the lifespan of the lower blade member 310.

In addition, because the upper blade member 320 cuts the overlapping portion 1400 of the plate material, the load on the upper blade member 320 during cutting is large.

The present invention was made in consideration of the above problems, and aims to provide a technology that reduces the load on the blade member when cutting steel plates when manufacturing steel sheet piles.

In order to solve the above problems, the present invention includes an uncoiling step of unwinding a strip-shaped steel sheet from a coil roll, a press forming step of pressing each of the two side ends of the steel sheet extending along the unwinding direction to form at least one hole, a roll forming step of rolling each of the side ends with the hole formed therein to bend the steel sheet so that they face each other at a predetermined distance at the side ends to form a joint, and a cutting step of inserting a lower blade member at a position that does not overlap with the hole, and bringing an upper blade member close to the steel sheet from the opposite side to the lower blade member at the position of the hole at the side end to cut the steel sheet in the width direction, and is characterized in that in the roll forming step, the steel sheet is folded so that the side end, including the side edge, overlaps with the hole in the approach direction of the upper blade member in the cutting step.

In addition, in the press forming step, two holes may be formed side by side in the width direction of the steel plate at each side end, and in the roll forming step, the steel plate may be folded so that the two holes do not overlap with each other in the approach direction of the upper blade member.

In addition, in the press forming step, multiple slits may be formed across the width of the steel plate between the holes at the two side ends.

Circular holes may also be formed during the press molding step.

This invention reduces the burden on the cutting member when cutting steel plate.

FIG. 2 is a plan view of a steel sheet pile manufactured by the method according to the first embodiment. FIG. 2 is a perspective view of the tip of the steel sheet pile shown in FIG. 1 . 1 is a flowchart showing manufacturing steps of a steel sheet pile. FIG. 2 is a plan view of the steel sheet after the press forming step. FIG. 2 is a plan view of the steel sheet after the roll forming step. 5 is a schematic diagram for explaining a method of cutting the steel plate in the cutting step. FIG. 1 is a flowchart showing conventional manufacturing steps of a steel sheet pile. FIG. 10 is a plan view of a steel sheet in which slits have been formed in the press forming step of the method according to the second embodiment. FIG. 10 is a plan view of a steel sheet in which two holes have been formed in the press forming step of the method according to the third embodiment. FIG. 2 is a plan view of the steel sheet after the roll forming step. 5 is a schematic diagram for explaining a method of cutting the steel plate in the cutting step. FIG. FIG. 1 is a schematic diagram for explaining a steel sheet formed by a roll forming machine in a conventional manufacturing method. FIG. 1 is a schematic diagram for explaining a method for cutting a steel plate in a conventional manufacturing method.

Below, an embodiment of the present invention will be described with reference to the drawings.

Figure 1 is a plan view of a steel sheet pile 100 manufactured by the method according to the first embodiment. For ease of explanation, the length direction of the steel sheet pile 100 is referred to as the "extension direction L", and the direction intersecting the extension direction L is referred to as the "width direction W".

The steel sheet pile 100 is used in various construction projects, such as quay wall construction, retaining wall construction, and foundation construction. The steel sheet pile 100 is driven into the ground along the extension direction L.

Figure 2 is a perspective view of the tip of the steel sheet pile 100 shown in Figure 1. The steel sheet pile 100 has a web portion 110, a pair of flange portions 120, and a pair of joint portions 130. The web portion 110 extends in the width direction W of the steel sheet pile 100. The web portion 110 has two flat portions 111 and a raised portion 112. The raised portion 112 is located between the two flat portions 111. The raised portion 112 extends along the extension direction L. The raised portion 112 is formed in an approximately U-shape when the steel sheet pile 100 is viewed in the extension direction L.

The pair of flange portions 120 extend along the extension direction L at both ends of the web portion 110 in the width direction W. The flange portions 120 are bent so as to stand upright relative to the web portion 110. The flange portions 120 are bent toward the side where the raised portion 112 is raised.

The ends of each flange portion 120 on the opposite side to the web portion 110 are bent away from each other to form a joint portion 130. The joint portion 130 is folded back toward the web portion 110. The cross-sectional shape of the joint portion 130 is approximately U-shaped. Adjacent steel sheet piles 100 are connected to each other via the joint portion 130.

The joint portion 130 has an extension portion 131, a curved portion 132, and an opposing portion 133. The extension portion 131 is folded back in the width direction W on the opposite side of the raised portion 112 relative to the flange portion 120. The extension portion 131 extends in the width direction W approximately parallel to the flat portion 111 of the web portion 110.

The curved portion 132 extends from one end of the extension portion 131 opposite the flange portion 120 toward the web portion 110. The curved portion 132 is rounded and convex toward the opposite side from the raised portion 112 in the width direction W.

The facing portion 133 extends from one end of the curved portion 132 opposite the extending portion 131 toward the flange portion 120. The facing portion 133 faces the extending portion 131 at a predetermined distance from the extending portion 131. A space S is defined by the flange portion 120 and the joint portion 130. The surface of the facing portion 133 facing the width direction W is spaced apart from the flange portion 120. In this embodiment, the joint portion 130 includes the extending portion 131, the curved portion 132, and the facing portion 133.

When connecting steel sheet piles 100 in the width direction W, the steel sheet piles 100 are connected with the raised portions 112 raised in opposite directions. The opposing portion 133 of one joint portion 130 enters the space S between the adjacent steel sheet piles 100, connecting them to each other.

A notch 134 is formed on the edge of the joint part 130 in the extension direction L. The notch 134 is formed along the extension direction of the approximately U-shaped joint part 130. The extension direction of the notch 134 extends along the extension direction L from the end face 140 facing the extension direction L of the steel sheet pile 100, and changes to the width direction W in a rounded manner.

Next, a manufacturing method of the steel sheet pile 100 will be described. FIG. 3 is a flowchart showing the manufacturing steps of the steel sheet pile 100. The manufacturing method according to this embodiment includes an uncoiling step S1 in which a strip-shaped steel plate 200 is unwound from a coil roll, a press forming step S2 in which two side ends 210 of the steel plate 200 extending along the unwinding direction (extension direction) L are each press-formed to form at least one hole 220, and a press forming step S3 in which each of the side ends 210 in which the hole 220 is formed is roll-formed, and the steel plate 200 is bent at the side ends 210 so that they face each other with a predetermined gap between them to form a joint portion 130. The method includes a roll forming step S3 in which the lower blade member 310 is inserted at a position where it does not overlap the hole 220, and a cutting step S4 in which the upper blade member 320 is brought close to the steel plate 200 from the opposite side to the lower blade member 310 at the position of the hole 220 in the side end 210 to cut the steel plate 200 in the width direction W. In the roll forming step S3, the steel plate 200 is bent so that the side end 210, including the side edge 211, overlaps with the hole 220 in the approach direction A of the upper blade member 320 in the cutting step S4. The manufacturing method of the steel sheet pile 100 will be specifically described below.

A coil roll (not shown) formed by winding a long steel sheet 200 into a roll is set in an uncoiler. First, the steel sheet 200 is unwound from the coil roll by the uncoiler (uncoil step S1). The steel sheet 200 unwound from the uncoiler is processed sequentially on the production line.

The unwound steel plate 200 is sent to a press device. In the press device, holes 220 (prenotches) are formed in the steel plate 200 (press forming step S2). Figure 4 is a plan view of the steel plate 200 after the press forming step S2. By applying press working to the steel plate 200 using the press device, holes 220 are formed in the two side ends 210 of the steel plate 200 in the width direction W.

The hole 220 is generally oval in plan view. Here, "oval" refers to a shape in which parallel sides spaced apart from each other in the extension direction L are connected by an arc in the width direction W. Note that the shape of the hole 220 is not limited to an oval, and may be circular or elliptical.

The distance between the sides of the holes 220 that are spaced apart in the extension direction L and extend in the width direction W is, for example, equal to or greater than the thickness of the cutting blade (upper blade member 320), and the maximum distance between the arc portions of the holes 220 in the width direction W is, for example, within a range of two to four times the thickness of the cutting blade. The position at which the holes 220 are formed in the extension direction L is determined according to the length of the steel sheet pile 100 to be manufactured.

The holes 220 formed in each side end 210 of the steel plate 200 in the width direction W are formed at the same position in the extension direction L. The holes 220 are formed, for example, at a predetermined interval from the side edge 211 of the steel plate 200 along the extension direction L.

The steel plate 200, which has been subjected to the press forming step S2 and has holes 220 formed therein, is sent to a roll forming machine. FIG. 5 is a plan view of the steel plate 200 after the roll forming step S3. The steel plate 200 is roll formed by the roll forming machine to form the web portion 110 (raised portion 112), flange portion 120, and joint portion 130 in the steel plate 200 (roll forming step S3).

The tip side of the side end portion 210 in the width direction W is folded outward in the width direction W relative to the flange portion 120, and then further folded toward the web portion 110, and then the tip of the side end portion 210 is folded back so that the side edges 211 of the two side end portions 210 face each other in the width direction W.

As a result, the side ends 210 of the steel plate 200 face each other at a predetermined distance in the thickness direction of the steel plate 200. This forms a joint 130 in the steel plate 200. A space S is formed inside the joint 130. When the steel sheet piles 100 are connected in the width direction W, the joints 130 of adjacent steel sheet piles 100 are connected to each other via the space S.

The joint portion 130 is formed by bending the steel plate 200 so that the side end portion 210, including the side edge 211, overlaps the hole 220 in the approach direction A in which the upper blade member 320 approaches the steel plate 200 in the cutting step S4 described below. When the joint portion 130 is formed, the side edge 211 of the steel plate 200 is located outside the edge of the hole 220 located toward the center of the steel plate 200 in the width direction W.

The hole 220 in the joint part 130 starts from the flange part 120 and extends from the extension part 131 of the joint part 130 to the curved part 132. At the position of the hole 220, the facing part 133 of the joint part 130 does not face any part of the steel plate 200 in the approach direction A, and is exposed through the hole 220 in the extension part 131 and the curved part 132.

The steel plate 200 with the joint 130 formed through the roll forming step S3 is sent to a cutting machine. In the cutting machine, the steel plate 200 is cut to a predetermined length to separate individual steel sheet piles 100 from the steel plate 200 (cutting step S4). Figure 6 is a schematic diagram for explaining the method of cutting the steel plate 200 in the cutting step S4. The steel plate 200 is cut by the cutting machine along an imaginary line V1 (see Figure 5) that connects the two holes 220 in the width direction W.

The cutter is provided with blade members (lower blade member 310 and upper blade member 320). The steel plate 200 fed to the cutter is supported from below by the lower blade member 310. The lower blade member 310 has a support body portion 311 and an insertion portion 312. The support body portion 311 mainly supports the web portion 110 and the flange portion 120 of the steel plate 200 from below.

The insertion portion 312 is inserted into the space S of the joint portion 130. When the insertion portion 312 of the lower blade member 310 is inserted into the space S of the joint portion 130, the insertion portion 312 is not exposed through the hole 220 of the steel plate 200. In other words, the insertion portion 312 is covered by the joint portion 130.

The upper blade member 320 approaches the steel plate 200 supported by the lower blade member 310 from below. In the cutting step S4, the lower blade member 310 is inserted into the space S of the joint portion 130, and the upper blade member 320 approaches the steel plate 200 from the opposite side to the lower blade member 310 to cut the steel plate 200. The approach direction A of the upper blade member 320 to the steel plate 200 and the lower blade member 310 is, for example, a direction from above to below in the vertical direction.

As shown in FIG. 7, which is a flowchart showing the conventional manufacturing steps of a steel sheet pile, the conventional manufacturing method includes an uncoiling step S10, a roll forming step S30, and a cutting step S40, and does not include a step corresponding to the press forming step S2 in the above embodiment. Therefore, as shown in FIG. 13, the steel plate 1000 does not have the hole 220 that was formed in the steel plate 200 in the above embodiment. In other words, in the joint portion 1300 of the steel plate 1000, the extension portion 1311 and the facing portion 1313 always face each other in the approach direction A along the extension direction L of the steel plate 1000.

In the cutting step S40 of the conventional manufacturing method, the upper blade member 320 first cuts the extension portion 1311, then cuts the curved portion 1312, and finally cuts the opposing portion 1313. Therefore, the load on the lower blade member 310 by the upper blade member 320 during one cutting operation is first transmitted to the insertion portion 312 when the extension portion 1311 is cut, and then transmitted to the insertion portion 312 via the extension portion 1311 when the opposing portion 1313 is cut.

In the conventional cutting step S40, the upper blade member 320 must cut two parts of the joint part 430, the extension part 1311 and the opposing part 1313, at the same location in one cutting step S40. Therefore, the part of the upper blade member 320 that cuts the extension part 1311 and the opposing part 1313 of the joint part 1300 is subjected to a larger load during cutting than other parts.

In addition, the transition portion (neck portion) 313 from the support body portion 311 to the insertion portion 312 of the lower blade member 310 is thinner than other portions. In one cutting step S40, two impacts are transmitted to the transition portion 313 by cutting the extension portion 1311 and the opposing portion 1313. Repeated cutting step S40 also tends to increase the accumulation of fatigue in the neck portion 313 of the lower blade member 310.

In contrast, according to the manufacturing method of this embodiment, in the cutting step S4, the upper blade member 320 cuts the steel plate 200 at the position of the hole 220, and does not cut the extension portion 131 that covers the insertion portion 312 of the lower blade member 310. Therefore, the portion of the joint portion 130 that is cut by the upper blade member 320 is mainly the opposing portion 133.

For example, if the hole 220 is formed in a quadrilateral shape such as a rectangle, stress may concentrate at the corners when cutting, causing unintended cracks in the steel plate 200. The hole 220 formed in the press forming step S2 of the manufacturing method according to the above embodiment is oval and does not have corners. Therefore, it is possible to avoid stress concentrating on the edge of the hole 220 when cutting.

Although the preferred embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and includes all aspects included in the concept of the present invention and the scope of the claims. Below, differences from the manufacturing method of the first embodiment will be mainly described, and the same parts will be denoted by the same reference numerals and will not be described.

The manufacturing method according to the second embodiment will be described with reference to Figure 8. Figure 8 is a plan view of a steel plate 200 in which a slit 230 has been formed in the press forming step S2 in the method according to the second embodiment.

In the manufacturing method according to the second embodiment, in the press forming step S2, multiple slits 230 are formed across the width direction W of the steel plate 200 between the holes 220 in the two side ends 210. The steel plate 200 with the slits 230 formed therein is then sent to the roll forming step S3 and finally to the cutting step S4.

The slits 230 are formed at a predetermined interval from each other in the width direction W. In the cutting step S4, the steel plate 200 is cut by a cutting machine along an imaginary line V2 that passes through the two holes 220 and the slits 230 in the width direction W.

By providing the slits 230, the load on the upper blade member 320 and the load on the steel plate 200 by the upper blade member 320 can be reduced.

The manufacturing method according to the third embodiment will be described with reference to Figure 9. Figure 9 is a plan view of a steel plate 200 in which two holes 240 are formed in the press forming step S2 in the method according to the third embodiment. In the press forming step S2, two holes 240 are formed side by side in the width direction W of the steel plate 200 in each side end 210.

The hole 240 has a generally oval shape in a plan view. Here, "oval" refers to a shape in which parallel sides spaced apart from each other in the extension direction L are connected by an arc in the width direction W. Note that the shape of the hole 240 is not limited to an oval shape, and may be a circle or an ellipse.

The distance between the sides of the holes 240 that are spaced apart in the extension direction L and extend in the width direction W is, for example, equal to or greater than the thickness of the cutting blade (upper blade member 320), and the maximum distance between the arc portions of the holes 240 in the width direction W is, for example, within a range of 1 to 1.5 times the thickness of the cutting blade. The positions at which the holes 240 are formed in the extension direction L are determined according to the length of the steel sheet pile 100 to be manufactured. The distance between each hole 240 at each side end 210 in the width direction W is, for example, 10 mm, and may be 10 mm or more.

The holes 240 formed in each side end 210 of the steel plate 200 in the width direction W are formed at the same position in the extension direction L. The holes 240 are formed, for example, at a predetermined interval from the side edge 211 of the steel plate 200 along the extension direction L.

In the roll forming step S3, the side edge portion 210 of the steel plate 200 is bent so that the two holes 240 do not overlap each other to form the joint portion 130. Figure 10 is a plan view of the steel plate 200 after the roll forming step S3.

Figure 11 is a schematic diagram for explaining the cutting method of the steel plate 200 in the cutting step S4. One of the two holes 240 is formed in the extending portion 131, and the other hole 240 is formed in the transition portion from the curved portion 132 to the facing portion 133. The two holes 240 do not overlap in the approach direction A, and the tip of the facing portion 133 overlaps with the hole 240 in the extending portion 131. As a result, the steel plate 200 of the joint portion 130 at the cutting position does not overlap in the approach direction A of the upper blade member 320.

The amount of cutting of the steel plate 200 by the upper blade member 320 in the approach direction A can be reduced, so the load on the lower blade member 310 and the upper blade member 320 can be reduced.

In addition, the configurations of the above embodiments may be appropriately and selectively combined to achieve at least some of the above-mentioned problems and effects.

100 Steel sheet pile, 110 Web portion, 120 Flange portion, 130 Joint portion, 200 Steel plate, 210 Side edge portion, 211 Side edge, 220, 240 Hole, 230 Slit, 310 Lower blade member, 320 Upper blade member

Claims (4)

an uncoiling step in which a strip-shaped steel sheet is unwound from the coil roll;
a press forming step of pressing two side ends of the steel plate extending along the unwinding direction to form at least one hole;
a roll forming step of bending the steel plate by roll forming each of the side ends in which the holes are formed, so that the portions forming the side ends face each other at a predetermined interval in the thickness direction of the steel plate , thereby forming a joint portion;
a cutting step of positioning the lower blade member such that an insertion portion, which is a part of the lower blade member, is covered by the joint portion when the insertion portion is inserted into a space inside the joint portion, and then cutting the steel plate in the width direction by bringing an upper blade member close to the steel plate from the opposite side to the lower blade member in the thickness direction at a position of the hole in the side end portion that is shifted from a position at which the lower blade member is positioned in the unwinding direction;
Including,
the roll forming step comprises bending the steel plate such that a portion of the side end portion including a side edge overlaps the hole in an approach direction of the upper blade member in the cutting step. In the press forming step, two holes are formed side by side in the width direction of the steel plate at each side end,
The manufacturing method according to claim 1 , wherein in the roll forming step, the steel plate is bent such that the two holes do not overlap each other in the approach direction. The manufacturing method described in claim 1 or 2, characterized in that in the press forming step, multiple slits are formed across the width of the steel plate between the holes at the two side ends. The manufacturing method described in any one of claims 1 to 3, characterized in that a circular hole is formed in the press molding step.

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