JP7632985B2 - Manufacturing method of hat-shaped steel sheet pile and steel sheet pile wall - Google Patents

Description

The present invention relates to a method for manufacturing hat-shaped steel sheet piles and steel sheet pile walls.

Hat-shaped steel sheet piles are widely used in civil engineering and construction work to build walls for retaining soil and water blocking. Hat-shaped steel sheet piles are driven into the ground during driving, so a technique has been proposed to improve workability by reducing the penetration resistance. For example, Patent Document 1 describes a technique for suppressing the earth discharge pressure during driving and improving workability by setting the flange angle, i.e., the angle between the flange and the web and the arm, so that the intersection of the perpendicular lines passing through the center of each flange in the cross section of the hat-shaped steel sheet pile is located outside the cross section of the groove of the hat-shaped steel sheet pile. Patent Document 2 also describes a technique for minimizing the penetration resistance by optimizing the flange angle. Patent Document 3 describes a technique for setting the flange angle based on an economic index and a workability index that indicates the penetration resistance at the bottom end of the steel sheet pile. Patent Document 4 describes a technique for setting the cross-sectional shape of a steel sheet pile that is excellent in at least one of the performances of economy and workability, based on the relationship between an economic evaluation index and a workability evaluation index that indicates the ratio of the blockage resistance acting on the bottom end of the steel sheet pile during driving to the cross-sectional area.

Patent No. 3488230 Patent No. 3488233 Patent No. 5764945 JP 2014-148798 A

The techniques described in the above Patent Documents 1 to 4 all focus on the behavior of steel sheet piles in the ground, and aim to improve workability by reducing the penetration resistance and blockage resistance that act after the steel sheet pile is penetrated into the ground. In other words, as a method for evaluating the workability of steel sheet piles, the focus has been only on the mechanism of inserting the steel sheet pile into the ground, and the optimum steel sheet pile shape has been sought based on the relationship with the ground resistance and soil particle behavior around the steel sheet pile. However, according to the knowledge obtained by the inventors, in addition to the behavior of the steel sheet pile in the ground, the behavior above ground during installation also affects the workability. In other words, the actual installation of the steel sheet pile proceeds in a manner in which the steel sheet pile is installed in the ground and the state where it protrudes above ground proceed in parallel, and the workability of the steel sheet pile is affected by the coupled behavior of the steel sheet pile in the ground and above ground. Specifically, it was found that when steel sheet piles are driven while being connected widthwise with joints, horizontal deflection deformation occurs in the hat-shaped steel sheet piles, which are driven while the joints are restrained to the previously driven steel sheet pile, reducing workability.

Specifically, if deformation such as twisting or bending occurs in the hat-shaped steel sheet pile, the penetration resistance from the ground from the bottom end of the steel sheet pile and the sides of the steel sheet pile during driving, and the fitting resistance with the joints of the steel sheet pile driven beforehand, may increase. In addition, if deformation such as bending or twisting occurs in the hat-shaped steel sheet pile above ground, the construction machine such as a vibro hammer may tilt or swing, and the vibration energy of the construction machine, which is originally used to vibrate the hat-shaped steel sheet pile in the vertical direction, may be lost as energy in the horizontal vibration and rotational behavior of the hat-shaped steel sheet pile, resulting in a decrease in the penetration speed of the hat-shaped steel sheet pile into the ground. If the construction machine tilts or swings, a horizontal load is applied to the head of the steel sheet pile, which may increase the deflection and twisting behavior of the steel sheet pile, resulting in a vicious cycle of further increasing the loss of vibration energy. Therefore, to ensure good workability of steel sheet piles, it is important to suppress the deflection and torsional deformation of the steel sheet piles above ground as well as their behavior in the ground.

However, the behavior of the hat-shaped steel sheet pile above ground, which may cause such a decrease in workability, is not described in the above-mentioned Patent Documents 1 to 4. In evaluating the installation performance of a steel sheet pile, it has not been done to search for the optimal cross-sectional shape of the steel sheet pile by looking at the overall behavior of the steel sheet pile, including the aboveground part, as well as the behavior in the ground. One reason for this is that when the cross section of the steel sheet pile is small, the position where the construction machine supports the steel sheet pile is not significantly eccentric from the cross-sectional center of gravity of the steel sheet pile, and therefore deformation such as bending and twisting of the steel sheet pile that affects the installation performance is unlikely to occur in the aboveground part. Therefore, it has been thought that the installation performance of the steel sheet pile is dominated by resistance from the ground. In fact, if the steel sheet pile is small, the cross-sectional deformation of the steel sheet pile during installation is not significantly exposed in the aboveground part, and the relationship between the deformation behavior in the aboveground part and the installation performance has not been paid attention to, and there has been no knowledge about the relationship between the two. However, in recent years, the cross-section of hat-shaped steel sheet piles has become larger, which has led to increased deformation behavior, such as twisting and bending, of hat-shaped steel sheet piles above ground, which may affect construction workability.

The present invention aims to provide a new and improved manufacturing method for hat-shaped steel sheet piles and steel sheet pile walls that can improve workability by reducing the horizontal deflection deformation that occurs above ground when the hat-shaped steel sheet piles are driven.

According to an aspect of the present invention, a hat-shaped steel sheet pile includes, in a cross section perpendicular to the longitudinal direction, a web extending along the width direction on a first side in the depth direction, a pair of flanges extending from both ends of the web in the width direction to both sides in the width direction and toward a second side in the depth direction, a pair of arms extending from each end of the pair of flanges on the second side in the depth direction along the width direction and toward both sides in the width direction, and a fitting joint formed at an end of each of the pair of arms opposite to the pair of flanges. The cross section of the hat-shaped steel sheet pile has a second moment of area I ( ^cm4 ), a distance d (cm) between a straight line corresponding to a surface of the second side in the depth direction of the pair of arms in the cross section and the centroid of the hat-shaped steel sheet pile, and an effective width W (cm) of the hat-shaped steel sheet pile satisfy the relationship of the following formula (i), in which the effective width W is 115 cm or more, and the second moment of area I is greater than 9500 ^cm4 and smaller than 40000 ^cm4 .
d/W≦4.75× ^10-5 ×I/d+0.085...(i)

In the above-mentioned hat-shaped steel sheet pile, the area second moment I, the distance d, and the effective width W may satisfy the relationships of the following formulas (ii) and (iii).
d/W≦1.90×10 ^-5 ×I/d+0.111...(ii)
I/d≧828...(iii)

According to another aspect of the present invention, there is provided a method for manufacturing a steel sheet pile wall using the above-mentioned hat-shaped steel sheet pile. The method for manufacturing a steel sheet pile wall may include a step of driving the hat-shaped steel sheet pile into the ground while engaging only one of the fitting joints of the hat-shaped steel sheet pile with the fitting joint of the steel sheet pile that has been driven in advance.

The above-mentioned configuration improves workability by reducing the horizontal deflection deformation that occurs in the aboveground portion when driving hat-shaped steel sheet piles.

FIG. 2 is a cross-sectional view of a hat-shaped steel sheet pile according to one embodiment of the present invention. FIG. 2 is a diagram for explaining a fitting center in a fitting joint of the hat-shaped steel sheet pile shown in FIG. 1 . FIG. 13 is a diagram showing the boundary conditions of the hat-shaped steel sheet pile during driving, and conceptually explaining the engagement with the preceding sheet pile and the gripping state of the hat-shaped steel sheet pile by the vibro hammer. FIG. 13 is a diagram for conceptually explaining the horizontal deflection deformation that occurs in a hat-shaped steel sheet pile during driving. 1 is a graph in which the comparative examples and examples of the present invention are plotted with the ratio I/d of the area second moment I to the distance d on the horizontal axis and the deflection amount f shown as a ratio to the deflection amount generated in a conventional hat-shaped steel sheet pile on the vertical axis. 1 is a graph plotting comparative examples and examples of the present invention with the ratio I/d of the area second moment I to the distance d on the horizontal axis and the ratio d/W of the distance d to the effective width W on the vertical axis. This graph shows only the examples in which the deflection amount f is reduced to less than 80% of that of the conventional hat-shaped steel sheet pile, out of the examples shown in the graph of FIG. 6 .

A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings. Note that in this specification and the drawings, components having substantially the same functional configuration are designated by the same reference numerals to avoid redundant description.

Figure 1 is a cross-sectional view of a hat-shaped steel sheet pile according to one embodiment of the present invention. As shown in Figure 1, the hat-shaped steel sheet pile 1 includes, in a cross section perpendicular to the longitudinal direction (z direction in the figure), a web 2 extending along the width direction (x direction in the figure) on a first side in the depth direction (the back side in the y direction in the figure), flanges 3A, 3B extending from both ends of the web 2 in the width direction to both sides in the width direction and toward a second side in the depth direction (the front side in the y direction in the figure) and forming a flange angle θ (acute angle side) with the width direction, arms 4A, 4B extending from the respective ends of the flanges 3A, 3B on the second side in the depth direction along the width direction and toward both sides in the width direction, and fitting joints 5A, 5B formed at the ends of the arms 4A, 4B opposite to the flanges 3A, 3B.

As described later, the area moment of inertia I ( ^cm4 ) of the hat-shaped steel sheet pile 1 in this cross section, the distance d (cm) between the straight line L _A corresponding to the surface of the second side in the depth direction of the arms 4A, 4B in the cross section (the front side in the y direction in the figure) and the centroid C of the hat-shaped steel sheet pile 1, and the effective width W (cm) of the hat-shaped steel sheet pile 1 satisfy the relationship of the following formula (1). Note that the effective width W is equal to the distance between the fitting centers E _A and E _B.
d/W≦4.75×10 ^-5 ×I/d+0.085...(1)

Here, due to manufacturing errors, the straight line L _A may not necessarily strictly coincide with the faces of the actual arms 4A and 4B. However, even in such a case, for example, in the cross section of the hat-shaped steel sheet pile 1 shown in the design drawing, the second side faces in the depth direction of the arms 4A and 4B are on the same straight line, and it is possible to specify the straight line L _A corresponding to these faces. In this case, the extension direction of the arms 4A and 4B shown in the design drawing coincides with the width direction of the hat-shaped steel sheet pile 1. In addition, in the hat-shaped steel sheet pile 1 driven into the ground after construction, for example, due to deformation of the arms 4A and 4B during construction, for example, at the head end face of the hat-shaped steel sheet pile 1 exposed above ground, the second side faces in the depth direction of the arms 4A and 4B may not strictly coincide with each other. However, even in this case, it is possible to specify the straight line L A corresponding to the second side faces in the depth direction of the arms 4A and 4B shown on the same straight line in the design drawing showing the _state before driving, for example. When design drawings are not used, the straight line connecting the fitting centers E _A and E _B located at the respective ends of the arms 4A and 4B at the head end face of the hat-shaped steel sheet pile 1 exposed above ground is taken as the designed thickness center line L _C of the arms 4A and 4B (see Figure 2), and the straight line L _A can be identified by translating the thickness center line L _C by half the thickness of the arms 4A and 4B toward the second side in the depth direction.

When the shape of the hat-shaped steel sheet pile 1 shown in Figure 1 is geometrically valid, the arm length Ba, effective width W, web length Bw, height H, and flange angle θ satisfy the relationship W-Bw-2H/tan θ>0. Here, height H is the height of the cross section of the hat-shaped steel sheet pile 1, including the plate thickness of the web 2 and arms 4A, 4B, but not including the overhang of the fitting joints 5A, 5B.

2 is a diagram for explaining the fitting center in the fitting joint of the hat-shaped steel sheet pile shown in FIG. 1. As shown in the figure, the fitting joint 5A of the hat-shaped steel sheet pile 1 is fitted with the fitting joint 5B of another hat-shaped steel sheet pile 1 that is driven adjacent to it. The fitting center _EA of the fitting joint 5A can be defined as a point on the design plate thickness center line LC of the arm 4A and the arm 4B, which is located midway between the end position of the arm 4A where the fitting joint 5A is formed and the end position of the arm 4B where the virtual fitting joint 5B is formed, when the arm 4B and the fitting joint 5B that fit _thereto are virtually arranged. The fitting center _EB of the fitting joint 5B located on the opposite side of the hat-shaped steel sheet pile 1 can be defined in the same way. As described above, the fitting centers _EA and _EB are related to the effective width W of the hat-shaped steel sheet pile 1.

Figures 3 and 4 are diagrams for conceptually explaining the horizontal deflection deformation that occurs in a hat-shaped steel sheet pile during driving. Figure 3 is a plan view of a hat-shaped steel sheet pile 1 showing the boundary conditions that cause horizontal deflection deformation in the hat-shaped steel sheet pile, and Figure 4 is a side view of the hat-shaped steel sheet pile 1. As shown in Figures 3 and 4, the hat-shaped steel sheet pile 1 is driven by a vertical vibration load B applied from a vibro hammer 6 that clamps the flanges 3A and 3B at the upper end. In order to stably support the hat-shaped steel sheet pile 1, the vibro hammer 6 is positioned so that its position in the depth direction (y direction in the figure) approximately coincides with the centroid C of the cross section.

Here, a hat-shaped steel sheet pile 1P is driven in advance near the ground surface, and the hat-shaped steel sheet pile 1 is driven while fitting the fitting joint 5A to the fitting joint 5B of the hat-shaped steel sheet pile 1P. Therefore, near the ground surface, the fitting joint 5A of the hat-shaped steel sheet pile 1 is restrained from horizontal displacement by the fitting joint 5B of the hat-shaped steel sheet pile 1P. The fitting joint 5A is restrained from horizontal displacement by contacting with the fitting joint 5B at multiple points near the fitting center _EA . Therefore, the hat-shaped steel sheet pile 1 is restrained by the fitting joint and the ground at the longitudinal lower part protruding above ground. On the other hand, the centroid C, which is the point of application of the vibration load by the vibro hammer 6, is located a distance d away from the fitting joint part where the horizontal displacement is restrained in the depth direction, i.e., in the direction of the weak axis of the cross section of the hat-shaped steel sheet pile 1, so that according to this distance d, a bending moment M due to the vibration load B acts on the part of the hat-shaped steel sheet pile 1 above the upper end of the hat-shaped steel sheet pile 1P as shown in Fig. 4. As a result, a deflection f in the depth direction (y direction in the figure) occurs in the hat-shaped steel sheet pile 1. If the deflection f becomes large, part of the vertical vibration load B by the vibro hammer 6 is converted into horizontal vibration, and the vibration load in the driving direction is not effectively transmitted into the ground, resulting in energy loss and reduced workability.

According to the experience of the inventors, when a conventional hat-shaped steel sheet pile of 16 m in length was being driven with a vibro hammer suspended from a crawler crane with a vibration load of 33 kN and a maximum amplitude of 6 mm in the vertical direction, when the hat-shaped steel sheet pile engaged with the adjacent hat-shaped steel sheet pile at a total of 6 m (5 m underground and 1 m above ground), the vibration in the depth direction of the remaining 10 m above the top end of the adjacent hat-shaped steel sheet pile increased and reached a maximum amplitude of 6 mm. As a result, the vibro hammer swung and the vibration load was no longer effective, and the driving speed of the hat-shaped steel sheet pile decreased.

In this embodiment, in order to prevent deterioration of workability, the cross-sectional shape of the hat-shaped steel sheet pile 1, which can reduce the deflection amount f more than the conventional hat-shaped steel sheet pile, was examined as a cantilever model in which the hat-shaped steel sheet pile protruding above ground is a fixed end whose lower end is restrained by the fitting joint part with the preceding sheet pile and the ground, and the upper end is a free end that receives the bending moment due to the vibration load. The inventors focused on the following points in the examination. First, in order to reduce the horizontal deflection amount f against the bending moment M as shown in FIG. 4, it is advantageous to reduce the bending moment M and to increase the area secondary moment I of the hat-shaped steel sheet pile 1, which is an index of resistance to the bending moment M. Here, since the bending moment M is proportional to the distance between the joint fitting position and the cross-sectional centroid, which is the position where the steel sheet pile is gripped by the construction machine, the centroid distance d shown in FIG. 3 can be used as an index representing the bending moment M. In order to reduce the bending moment M, it is advantageous to reduce the centroid distance d. I/d, which combines the centroid distance d, which is an index of bending moment M, and the second moment of area I, is an index that reduces the amount of deflection f as the value increases.

On the other hand, we aimed not only to make a steel sheet pile that can reduce the amount of deflection, but also to make the cross section economical, so we aimed to make it larger in cross section and incorporated the effective width W as an indicator. By making it wider, the web width can be increased and the area ratio of the flange portion to a given width can be reduced, so that the geometric moment of area, i.e., bending rigidity, per given width can be ensured with a smaller cross-sectional area. In other words, a large geometric moment of area I can be obtained with an economical cross section. In other words, when the effective width W is large, even if the geometric moment of area per wall width is the same, the geometric moment of area I of a single hat-shaped steel sheet pile 1 (per piece) becomes larger, and the range of bending moment M that can keep the amount of deflection f within an acceptable range can be increased.

Here, since the bending moment M and the centroid distance d are proportional, increasing the centroid distance d increases the bending moment M, but if the effective width W is also increased in this case, the second moment of area I can be increased and the deflection amount f can be kept within an acceptable range. In other words, by keeping d/W below a specified value, the deflection amount f can be kept within an acceptable range.

Therefore, the following study is intended to identify the conditions for the cross-sectional shape of the hat-shaped steel sheet pile 1 that can reduce the amount of deflection f, focusing on the values of I/d and d/W.

The results of the study are shown in Tables 1 to 4. The study was carried out for the cases where the moment of inertia _IW per meter of wall width of the wall body in which hat-shaped steel sheet piles 1 are connected in the width direction is 10,000 cm ⁴ /m level, 25,000 ^{cm 4} /m level, 45,000 cm ^{4 /m level, and 50,000 cm 4} /m level, and examples in which the deflection f is reduced compared to the conventional hat-shaped steel sheet piles shown as Comparative Examples 1 to 4 are shown as Examples 1 to 32. The dimensions represented by the web thickness tw (cm), web width Bw (cm), and arm width Ba (cm) shown in Tables 1 to 4 are shown in FIG. 1.

5 is a graph plotting the above-mentioned Comparative Examples 1 to 4 and Examples 1 to 32, with the ratio I/d of the geometrical moment of area I (cm ⁴ ) to the distance d (cm) on the horizontal axis and the deflection amount f (comparison with the conventional example) on the vertical axis. Comparative Examples 1 to 4 are shown as points P1 to P4, and Examples 1 to 32 are shown divided into groups of points E1 to E7, points E8 to E16, points E17 to E29, and points E30 to E32 according to the level of the geometrical moment of area _IW . As shown in the graph in FIG. 5, although the value of I/d differs for each level of the geometrical moment of area _IW per 1 m of wall width, there was a tendency that within each level, the deflection amount f was reduced as the value of I/d increased.

6 is a graph plotting the above-mentioned Comparative Example 1 to Comparative Example 4 and Example 1 to Example 32, with the ratio I/d of the area second moment I (cm ⁴ ) to the distance d (cm) on the horizontal axis and the ratio d/W of the distance d (cm) to the effective width W (cm) on the vertical axis. In the graph of FIG. 6, points E1 to E32 showing the examples are included in the range of d/W≦4.75×10 ⁻⁵ ×I/d+0.085. In contrast, points P1 to P4 showing the comparative examples are in the range of d/W>4.75×10 ⁻⁵ ×I/d+0.085. Therefore, from the results of the above study, the following formula (1) can be specified as a condition for the cross-sectional shape of the hat-shaped steel sheet pile 1 that can reduce the deflection amount f.
d/W≦4.75×10 ^-5 ×I/d+0.085...(1)

Here, the area moment of area I increases in proportion to the square of the distance d, so the larger the area moment of area I, the larger d/W becomes. Also, since the rate of increase of the area moment of area I is greater than the rate of increase of the distance d, the larger the area moment of area I, the larger I/d becomes. In other words, I/d tends to increase with an increase in d/W. Therefore, in hat-shaped steel sheet piles, I/d and d/W are correlated indicators, and for example, in Comparative Examples 1 to 4 (points P1 to P4) in Figure 6, they are almost proportional. In hat-shaped steel sheet piles, when the width is increased to achieve an economical cross section while the value of d is increased to ensure a large area moment of area, there was no standard for how to appropriately determine the effective width W and distance d, respectively, in order to keep the deflection within an acceptable range. In the above study, it was found that from the viewpoint of reducing the amount of deflection f, it is effective to set d/W to a value equal to or less than a predetermined value determined according to I/d, and the relationship between I/d and d/W in formula (1) was defined as a condition for keeping the amount of deflection equal to or less than that which occurs in conventional steel sheet piles, providing a standard for determining the effective width W and distance d according to the moment of inertia I.

In addition, the above-mentioned Examples 1 to 32 include hat-shaped steel sheet piles 1 having a cross-sectional area moment of inertia _IW per meter of wall width of the wall bodies connected in the width direction of 10,000 ^cm4 /m, 25,000 ^cm4 /m, 45,000 ^cm4 /m, and 50,000 ^cm4 /m, but the cross-sectional area moment of inertia I of each hat-shaped steel sheet pile 1 (per piece) is in the range greater than 9,500 ^cm4 and less than 80,000 ^cm4 (9,500 ^cm4 < I < 80,000 ^cm4 ).

Furthermore, for the hat-shaped steel sheet pile with an expanded width, i.e., a so-called thin-walled, large cross section, it is preferable to make the cross section more compact when considering manufacturability. From this viewpoint, among the examples discussed above, it is more preferable that the area second moment I of the hat-shaped steel sheet pile 1 (per piece) is in the range of more than 9500 ^cm4 and less than 40000 ^cm4 (9500 ^cm4 < I < 40000 ^cm4 ).

Figure 7 is a graph in which only examples in which the deflection amount f (comparison with the conventional example) is less than 0.8, that is, the deflection amount f is reduced to less than 80% of the conventional hat-shaped steel sheet pile, are extracted from Examples 1 to 32 shown in the graph of Figure 6. Specifically, Examples 1 to 7, Examples 9 to 16, and Examples 22 to 32 are extracted. In the graph of Figure 7, points E1 to E7, E9 to E16, and E22 to E32 showing the extracted examples are included in the range of d/W≦1.90×10 ⁻⁵ ×I/d+0.111 and I/d≧828. In contrast, points P1 to P4 showing the comparative examples are in the range of d/W>1.90×10 ⁻⁵ ×I/d+0.111. Therefore, the following equations (2) and (3) can be specified as the conditions for the cross-sectional shape of the hat-shaped steel sheet pile 1 that can reduce the deflection amount f to a level at which a significant effect can be obtained in practical use, specifically to less than 80% of that of conventional hat-shaped steel sheet piles.
d/W≦1.90×10 ^-5 ×I/d+0.111 (2)
I/d≧828 (3)

The above study was carried out in the course of considering expanding the effective width W of the hat-shaped steel sheet pile 1 beyond the effective width of 90 cm of the conventional hat-shaped steel sheet pile in order to construct a more efficient and economical cross section than the conventional hat-shaped steel sheet pile, and therefore the effective width W is 100 cm or more in Examples 1 to 32. However, under the conditions of the above formulas (1) to (3), the cross section that reduces the amount of deflection more than the conventional hat-shaped steel sheet pile is defined only as the relationship between the ratio d/W of the effective width W to the distance d and the ratio I/d of the distance d to the area second moment I. Therefore, it is considered that the cross section shape that can ensure a more economical cross section than the conventional hat-shaped steel sheet pile can also be applied, for example, when the effective width W is less than 100 cm.

On the other hand, from the viewpoint of economical construction, it is desirable to be able to reuse existing construction machines even if the effective width of the hat-shaped steel sheet pile is expanded. As for pressing machines, which are a type of construction machine, those capable of an effective width of 90 cm (Comparative Example 1 to Comparative Example 4) are widely used, and as pressing machines that can be used for effective widths exceeding 90 cm, there are machines capable of effective widths of 115 cm to 146.1 cm. In other words, from the above viewpoint, it is preferable that the effective width W of the hat-shaped steel sheet pile is 115 cm or more.

According to the embodiment of the present invention described above, a hat-shaped steel sheet pile with a cross-sectional shape that effectively reduces horizontal deflection deformation that occurs during driving is provided. Such a hat-shaped steel sheet pile is particularly advantageous in a manufacturing method for a steel sheet pile wall that includes a process of driving the hat-shaped steel sheet pile into the ground while fitting only one of a pair of fitting joints of the hat-shaped steel sheet pile into the fitting joint of the steel sheet pile that was previously driven. In such a manufacturing method for a steel sheet pile wall, the position where the construction machine supports the steel sheet pile and applies a vertical vibration load is eccentric to the position where one joint of the hat-shaped steel sheet pile fits into the joint of the steel sheet pile that was previously driven, so a moment that causes deflection deformation is likely to occur in the hat-shaped steel sheet pile, but the application of the embodiment of the present invention can effectively suppress the deflection deformation.

By suppressing the deflection deformation of the hat-shaped steel sheet pile, the lateral vibration of the hat-shaped steel sheet pile above ground is reduced, and the driving energy from the construction machine is transmitted to the hat-shaped steel sheet pile with little loss and while efficiently utilizing the construction machine's force, the penetration speed of the hat-shaped steel sheet pile into the ground can be maintained high, and economical construction with good fuel efficiency of the construction machine is possible. In addition, by suppressing the deflection deformation of the hat-shaped steel sheet pile, the flapping of the hat-shaped steel sheet pile during driving is reduced, and noise and vibration associated with construction can be reduced. If the construction machine becomes larger due to the large cross-section of the hat-shaped steel sheet pile, noise and vibration may also increase, but by suppressing the deflection deformation of the hat-shaped steel sheet pile, construction with suppressed noise and vibration is possible.

In addition, by suppressing the flexural deformation of the hat-shaped steel sheet pile, it is possible to reduce the mating resistance with the joints of the steel sheet pile that was cast in advance, which reduces the resistance of the entire hat-shaped steel sheet pile when it is cast, and also prevents scraping and welding at the contact surfaces of the joints.

The above describes in detail preferred embodiments of the present invention with reference to the attached drawings, but the present invention is not limited to such examples. It is clear that a person with ordinary knowledge in the technical field to which the present invention pertains can conceive of various modified or revised examples within the scope of the technical ideas described in the claims, and it is understood that these also naturally fall within the technical scope of the present invention.

1... hat-shaped steel sheet pile, 2... web, 3A, 3B... flanges, 4A, 4B... arms, 5A, 5B... fitting joints, 6... vibro hammer, C... centroid, E _A , E _B ... fitting centers.

Claims (3)

A hat-shaped steel sheet pile,
In a cross section perpendicular to the longitudinal direction, the panel comprises a web extending along the width direction on a first side in the depth direction, a pair of flanges extending from both ends of the web in the width direction to both sides in the width direction and toward a second side in the depth direction, a pair of arms extending from each end of the pair of flanges along the width direction and toward both sides in the width direction on the second side in the depth direction, and fitting joints formed at the ends of each of the pair of arms opposite to the pair of flanges,
a second moment of area I ( ^cm4 ) of the hat-shaped steel sheet pile at the cross section, a distance d (cm) between a straight line corresponding to a second side surface of the pair of arms in the depth direction at the cross section and the centroid of the hat-shaped steel sheet pile, and an effective width W (cm) of the hat-shaped steel sheet pile satisfy the relationship of the following formula (i), the effective width W is 115 cm or more, and the second moment of area I is greater than 9,500 ^cm4 and smaller than 40,000 ^cm4 .
d/W≦4.75× ^10-5 ×I/d+0.085...(i) The hat-shaped steel sheet pile according to claim 1 , wherein the area second moment I, the distance d, and the effective width W satisfy the relationships of the following formulas (ii) and (iii).
d/W≦1.90×10 ^-5 ×I/d+0.111...(ii)
I/d≧828...(iii) A manufacturing method of a steel sheet pile wall using the hat-shaped steel sheet pile according to claim 1 or 2,
A manufacturing method for a steel sheet pile wall, comprising: a step of driving the hat-shaped steel sheet pile into the ground while engaging only one of the fitting joints of the hat-shaped steel sheet pile with a fitting joint of a steel sheet pile driven in advance.

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