WO2020045115A1

WO2020045115A1 - Hat-shaped steel sheet pile and production method for steel sheet pile wall

Info

Publication number: WO2020045115A1
Application number: PCT/JP2019/032111
Authority: WO
Inventors: 裕章中山; 典佳原田; 正和武野; 妙中　真治; 俊介森安
Original assignee: 日本製鉄株式会社
Priority date: 2018-08-31
Filing date: 2019-08-16
Publication date: 2020-03-05
Also published as: JPWO2020045115A1; JP7143888B2; JP2022120101A

Abstract

A hat-shaped steel sheet pile comprising, in a cross-section orthogonal to the longitudinal direction: a web extending along the width direction on a first side in the depth direction; a pair of flanges extending to both sides in the width direction from both ends of the web in the width direction and towards a second side in the depth direction; a pair of arms extending from each end section of the pair of flanges, in the width direction on the second side in the depth direction and towards both sides in the width direction; and a mating fitting formed in an end section of each of the pair of arms, on the opposite side to the pair of flanges. The cross-section second moment I of the hat-shaped steel sheet pile in cross-section, the distance d between the centroid of the hat-shaped steel sheet pile and a straight line corresponding to the surface on the second side of the pair of arms in the depth direction, in cross-section, and the effective width W of the hat-shaped steel sheet pile fulfil the relationship in formula (i) and the effective width W is at least 100 cm. d/W ≤ 4.75 × 10^–5 × I/d + 0.085 … (i)

Description

Hat-shaped steel sheet pile and method of manufacturing steel sheet pile wall

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

形 Hat-shaped steel sheet piles are widely used in civil engineering and construction work to construct walls for earth retaining and waterproofing. Since a hat-shaped steel sheet pile is made to penetrate into the ground at the time of driving, a technique for improving workability by reducing penetration resistance has been proposed. For example, in Patent Literature 1, in the cross section of the hat-shaped steel sheet pile, the flange angle, that is, the flange is positioned between the web and the arm such that the intersection of a perpendicular passing through the center of each flange is located outside the groove cross section of the hat-shaped steel sheet pile. There is described a technique for improving the workability by suppressing the earth pressure at the time of placing by setting an angle to be formed. Patent Literature 2 also discloses a technique for minimizing the penetration resistance by optimizing the flange angle. Patent Literature 3 describes a technique for setting a flange angle based on an economic index and a workability index indicating a penetration resistance at the lower end of a steel sheet pile. Patent Literature 4 discloses at least one of economy and workability based on a relationship between an economy evaluation index and a workability evaluation index indicating a ratio of a cross-sectional area of a closing resistance acting on a lower end of a steel sheet pile at the time of driving. A technique for setting the cross-sectional shape of a steel sheet pile having excellent performance is described.

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

All of the techniques described in Patent Documents 1 to 4 above focus on the behavior of steel sheet piles in the ground, and reduce the penetration resistance and blockage resistance acting after being made to penetrate the ground. The purpose is to improve workability. In other words, as a method of evaluating the workability of steel sheet piles, the focus has been on the mechanism of steel sheet pile insertion in the ground so far, and the optimum steel sheet pile is considered from the relationship with the ground resistance and soil particle behavior around the steel sheet pile. I've been looking for a sheet pile shape. However, according to the knowledge obtained by the present inventors, in addition to the behavior of the steel sheet pile in the ground, the behavior of the steel sheet pile on the ground portion during driving also affects the workability. In other words, in actual steel sheet pile driving, the situation where the steel sheet pile is being driven into the ground and the state where it is protruding above the ground proceed in a parallel fashion, and the workability of the steel sheet pile is It is affected by the coupled behavior of steel sheet piles inside and above the ground. Specifically, when the steel sheet pile is driven while being connected in the width direction with a joint, the hat-shaped steel sheet pile which is driven with the joint restrained by the steel sheet pile previously driven is horizontally It was found that the workability deteriorated due to the occurrence of flexural deformation.

Specifically, when deformation such as torsion or bending occurs in the hat-shaped steel sheet pile, the penetration resistance received from the ground from the bottom of the steel sheet pile at the lower end or from the side of the steel sheet pile at the time of driving, or the steel sheet pile previously driven There is a possibility that the fitting resistance with the joint increases. In addition, when deformation such as bending or torsion occurs in the hat-shaped steel sheet pile on the ground part, the construction machine such as a vibratory hammer tilts and swings, which originally causes the hat-shaped steel sheet pile to vibrate vertically. The vibration energy of the construction machine used in the construction may be lost as energy of horizontal vibration and rotation behavior of the hat-shaped steel sheet pile, and as a result, the penetration speed of the hat-shaped steel sheet pile into the ground may be reduced. When the construction machine is tilted or rocked, a horizontal load is applied to the steel sheet pile head, which increases the deflection and torsion behavior of the steel sheet pile, and further increases the loss of vibration energy. May fall into Therefore, in order to ensure good workability of the steel sheet pile, it is important to suppress not only the behavior in the ground but also the bending and torsional deformation of the steel sheet pile on the ground.

However, the behavior of the hat-shaped steel sheet pile on the ground portion, which may cause such deterioration in workability, is not described in Patent Documents 1 to 4 described above. In evaluating the driving performance of steel sheet piles, it has been conventional practice to look for not only the behavior in the ground but also the overall behavior of the steel sheet piles, including the ground part, and to search for the optimum steel sheet pile cross-sectional shape. Did not. One of the reasons is that, when the cross section of the steel sheet pile is small, the position at which the construction machine supports the steel sheet pile is not largely eccentric from the center of gravity of the cross section of the steel sheet pile, and therefore, the workability is affected at the ground part. This is because deformation such as bending and twisting of the steel sheet pile was difficult to occur. Therefore, the workability of steel sheet piles has been considered to be dominated by the resistance from the ground. In fact, if the steel sheet piles are small, the section deformation of the steel sheet piles at the time of driving is not significantly exposed on the ground, and no attention is paid to the relationship between the deformation behavior on the ground and the workability. However, there was no finding regarding the relationship between the two. However, in recent years, with the enlargement of the cross section of the hat-shaped steel sheet pile, the deformation behavior of the hat-shaped steel sheet pile in the ground portion, such as torsion and deflection, has been expanded, which may affect the workability.

Accordingly, the present invention provides a new and improved hat-shaped steel sheet pile and steel capable of improving workability by reducing a horizontal bending deformation generated on a ground portion when the hat-shaped steel sheet pile is driven. An object of the present invention is to provide a method for manufacturing a sheet pile wall.

According to an aspect of the present invention, a hat-shaped steel sheet pile includes, in a cross section orthogonal to a longitudinal direction, a web extending along a width direction on a first side in a depth direction, and a width direction from both ends in a width direction of the web. And a pair of flanges extending toward the second side in the depth direction, and both ends in the width direction along the width direction from respective ends of the pair of flanges on the second side in the depth direction. And a mating joint formed at the end of each of the pair of arms opposite the pair of flanges. The moment of inertia I (cm ⁴ ) of the cross section of the hat-shaped steel sheet pile in the cross-section, and the centroid of the hat-shaped steel sheet pile between the straight line corresponding to the second surface in the depth direction of the pair of arms in the cross section. The distance d (cm) and the effective width W (cm) of the hat-shaped steel sheet pile satisfy the relationship of the following expression (i), and the effective width W is 100 cm or more.
d / W ≦ 4.75 × 10 ⁻⁵ × I / d + 0.085 (i)

In the above-mentioned hat-shaped steel sheet pile, the second moment of area I, the distance d, and the effective width W may satisfy the following equations (ii) and (iii).
d / W ≦ 1.90 × 10 ⁻⁵ × I / d + 0.111 (ii)
I / d ≧ 828 (iii)
In the above hat-shaped steel sheet pile, it may also be effective width W is 115cm or more, greater moment of inertia I is more 9500Cm ^4, and may be smaller than 80000cm ^4.

According to another aspect of the present invention, there is provided a method for manufacturing a steel sheet pile wall using the above hat-shaped steel sheet pile. The method of manufacturing the steel sheet pile wall is to cast a hat-shaped steel sheet pile into the ground while fitting only one of the fitting joints of the hat-shaped steel sheet pile to the fitting joint of the steel sheet pile previously placed. May be included.

According to the above configuration, the workability can be improved by reducing the horizontal bending deformation generated on the ground portion when the hat-shaped steel sheet pile is driven.

It is sectional drawing of the hat-shaped steel sheet pile which concerns on one Embodiment of this invention. It is a figure for demonstrating the fitting center in the fitting joint of the hat-shaped steel sheet pile shown in FIG. It is a figure which shows the boundary condition of a hat-shaped steel sheet pile at the time of driving, and is a figure for conceptually explaining the fitting state with a preceding sheet pile, and the holding state of a hat-shaped steel sheet pile with a vibro hammer. It is a figure for conceptually explaining the horizontal deflection deformation which arises in a hat-shaped steel sheet pile at the time of driving. In the comparative example and the example of the present invention, the ratio I / d of the second moment of area I to the distance d was plotted on the horizontal axis, and the deflection f shown by the ratio of the deflection generated by the conventional hat-shaped steel sheet pile to the vertical axis. It is a graph plotted as an axis. It is the graph which plotted the comparative example and example of this invention on the axis of abscissa the ratio I / d of the area moment of inertia I and the distance d, and the axis of ordinate the ratio d / W of the distance d and the effective width W. 7 is a graph in which only an example in which the amount of deflection f is reduced to less than 80% of the conventional hat-shaped steel sheet pile among the examples shown in the graph of FIG. 6 is extracted.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the specification and the drawings, components having substantially the same function and configuration are denoted by the same reference numerals, and redundant description is omitted.

FIG. 1 is a sectional view of a hat-shaped steel sheet pile according to one embodiment of the present invention. As shown in FIG. 1, a hat-shaped steel sheet pile 1 has a cross section orthogonal to a longitudinal direction (z direction in the figure) and a width direction on a first side in a depth direction (a depth side in a y direction in the figure). The web 2 extends along the x direction (in the figure) and from both ends in the width direction of the web 2 toward both sides in the width direction and toward the second side in the depth direction (front side in the y direction in the figure). The

flanges

3A and 3B extend and form a flange angle θ (a sharp angle side) with the width direction, and the widthwise direction from the respective ends of the

flanges

3A and 3B on the second side in the depth direction. 4A and 4B extending toward both sides of the arm 4A, and

fitting joints

5A and 5B formed at ends of the

arms

4A and 4B opposite to the

flanges

3A and 3B, respectively.

As will be described later, the second moment of area I (cm ⁴ ) of the hat-shaped steel sheet pile 1 in this section and the second side in the depth direction of the

arms

4A and 4B (the front side in the y direction in the drawing) in the section. and distance d (cm) between the centroid C of the straight line L _a and hat-shaped steel sheet pile 1 which corresponds to the surface, the effective width W of the hat-shaped steel sheet pile 1 (cm), the following formula (1) Satisfy the relationship. Incidentally, the effective width W, fitting center _E A, equal to the distance between the _{E B.}
d / W ≦ 4.75 × 10 ⁻⁵ × I / d + 0.085 (1)

Here, the straight line L _A, due to manufacturing errors, there necessarily to arm 4A, even if they do not match exactly to the plane of 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 surfaces on the second side in the depth direction of the

arms

4A and 4B are on the same straight line, and these surfaces are it is possible to specify the straight line L _a corresponding to. In this case, the extending 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 the construction, the

arms

4A, 4B are deformed at the time of construction or the like, so that the

arms

4A, 4A, The surface on the second side in the depth direction of 4B may not be exactly on the same straight line. Shinashi while, that this case also, to identify the linear L _A corresponding to the surface of the second side of the design arm 4A shown on the same straight line in the drawing, 4B in the depth direction showing the status of, for example, punching設前Can be. If that is not based on the design drawing, at the head end face of the hat-shaped steel sheet pile 1 exposed on the ground, the arm 4A, fitting center E _A located at each end of _4B, the arm 4A of the straight line connecting the E _B , straight by the 4B thickness center line L _C of the design _(see FIG. 2), the thickness center line L _C depth direction of the second arm 4A to the side, is only translated 4B plate half of the thickness L _A can be specified.

When the shape of the hat-shaped steel sheet pile 1 shown in FIG. 1 is geometrically established, the arm length Ba, the effective width W, the web length Bw, the height H, and the flange angle θ are W−Bw− 2H / tan θ> 0. Here, the height H is the height of the cross section of the hat-shaped steel sheet pile 1 including the thickness of the web 2 and the

arms

4A and 4B and not including the overhang of the

fitting joints

5A and 5B.

FIG. 2 is a view for explaining a fitting center of the hat-shaped steel sheet pile shown in FIG. 1 in the fitting joint. As shown in the figure, the fitting joint 5B of another hat-shaped steel sheet pile 1 that is driven adjacent to the fitting joint 5B of the hat-shaped steel sheet pile 1 is fitted. Fitting center E _A fitting joint 5A, when placing the arms 4B and the fitting joint 5B fitted to virtually, and the end position of the arm 4A of the fitting joint 5A is formed, the virtual specific fitting joints 5B is positioned intermediate the end position of the arm 4B to be formed, it can be defined as a point on the thickness center line L _C design of the arms 4A and the arm 4B. Fitting the center of the fitting joint 5B located on the opposite side of the hat-shaped steel sheet pile 1 E _B can also be defined similarly. As mentioned above, fitting the center E _A, E _B is related to the effective width W of the hat-shaped steel sheet pile 1.

および FIGS. 3 and 4 are diagrams for conceptually explaining horizontal bending deformation occurring in the hat-shaped steel sheet pile during driving. FIG. 3 is a plan view of the hat-shaped steel sheet pile 1 showing a boundary condition that causes the hat-shaped steel sheet pile to bend in the horizontal direction. FIG. 4 is a side view of the hat-shaped steel sheet pile 1. As shown in FIGS. 3 and 4, the hat-shaped steel sheet pile 1 is driven by a vertical vibration load B applied from a vibrohammer 6 sandwiching the

flanges

3A and 3B at the upper end. In order to stably support the hat-shaped steel sheet pile 1, the vibratory hammer 6 is arranged so that the position in the depth direction (the y direction in the drawing) substantially matches the center C of the cross section.

Here, there is a hat-shaped steel sheet pile 1P previously driven near the ground surface, and the hat-shaped steel sheet pile 1 is driven while the fitting joint 5A is fitted to the fitting joint 5B of the hat-shaped steel sheet pile 1P. Is established. 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. Mating fitting 5A is constrained to horizontal displacement by contact at a plurality of points near the fitting joint 5B and the fitting center E _A. Therefore, the hat-shaped steel sheet pile 1 is restrained by the fitting joint portion and the ground at the lower portion in the longitudinal direction projecting to the ground portion. On the other hand, the centroid C, which is the point of application of the vibration load by the vibratory hammer 6, is located in the depth direction, that is, in the weak axis direction of the cross section of the hat-shaped steel sheet pile 1 from the fitting joint where horizontal displacement is restricted. As shown in FIG. 4, the bending moment due to the vibration load B is applied to the portion of the hat-shaped steel sheet pile 1 above the upper end of the hat-shaped steel sheet pile 1P according to the distance d. M acts. As a result, a deflection f in the depth direction (the y direction in the drawing) occurs in the hat-shaped steel sheet pile 1. When the deflection amount f increases, a part of the vertical vibration load B by the vibratory hammer 6 is converted into horizontal vibration, and the vibration load in the driving direction is not effectively transmitted to the ground, and energy loss occurs. Workability decreases.

According to the experience of the present inventors, a conventional hat-shaped steel sheet pile having a length of 16 m was driven with a vibratory hammer suspended from a crawler crane at a vibration load of 33 kN and a maximum amplitude of vertical vibration of 6 mm. When the shaped steel sheet pile is fitted to the adjacent hat-shaped steel sheet pile at a total of 6 m, 5 m in the ground and 1 m on the ground, the depth of the remaining 10 m above the upper end of the adjacent hat-shaped steel sheet pile is measured. The vibration increased and reached a maximum amplitude of 6 mm. As a result, the vibratory hammer rocked, and the vibration load did not act effectively. As a result, the driving speed of the hat-shaped steel sheet pile decreased.

In the present embodiment, in order to prevent the workability from deteriorating, the cross-sectional shape of the hat-shaped steel sheet pile 1 whose deflection f can be reduced compared to the conventional hat-shaped steel sheet pile is changed to a hat-shaped steel sheet projecting above the ground. The sheet pile was studied as a cantilever model in which the lower end was a fixed end restrained by the fitting joint with the preceding sheet pile and the ground, and the upper end was a free end subjected to bending moment due to vibration load. The points that the present inventors focused on in the study are as follows. First, in order to reduce the bending amount f in the horizontal direction against the bending moment M as shown in FIG. 4, the bending moment M must be reduced, and a hat-shaped steel that serves as an index of resistance to the bending moment M It is advantageous to increase the second moment of area I of the sheet pile 1. Here, since the bending moment M is proportional to the distance between the joint fitting position and the sectional centroid at which the construction machine holds the steel sheet pile, the centroid distance d shown in FIG. Can be used. In order to reduce the bending moment M, it is advantageous to reduce the centroid distance d. I / d, which is a combination of the centroid distance d and the second moment of area I, which is an index of the bending moment M, is an index that reduces the amount of deflection f as the value increases.

On the other hand, the aim was not only to make the steel sheet pile that can reduce the amount of deflection, but also to make it an economical cross section. By increasing the width, the web width can be increased and the area ratio of the flange portion to the predetermined width can be reduced, so that the secondary moment of area per predetermined width, that is, bending rigidity, can be secured with a smaller cross-sectional area. That is, a large area second moment I can be obtained in an economical section. In other words, when the effective width W is large, even when the second moment of area per wall width is the same, the second moment of area I of the hat-shaped steel sheet pile 1 (per sheet) becomes larger, and the amount of deflection is increased. The range of the bending moment M in which f can be suppressed to an allowable range can be increased.

Here, since the bending moment M and the centroid distance d are in a proportional relationship, the bending moment M increases as the centroid distance d increases, but if the effective width W also increases at this time, the secondary moment of area I decreases. By increasing the amount, the deflection amount f can be suppressed to an allowable range. That is, by suppressing d / W to a predetermined value or less, the deflection amount f can be suppressed to an allowable range.

Therefore, the following examination is intended to specify the conditions of the cross-sectional shape of the hat-shaped steel sheet pile 1 capable of reducing the deflection f, focusing on the values of I / d and d / W.

Tables 1 to 4 show the results of the study. Study, cross-sectional secondary moment _{I W} is 10000 cm ⁴ / m level per wall width 1m of wall linked a hat-shaped steel sheet pile 1 in the width direction, 25000 cm ⁴ / m level, 45000cm ⁴ / m level, and 50000 cm ⁴ / M level, and Examples 1 to 32 show examples in which the amount of deflection f was reduced as compared with the conventional hat-shaped steel sheet piles shown as Comparative Examples 1 to 4. The dimensions represented by the web thickness tw (cm), the web width Bw (cm), and the arm width Ba (cm) shown in Tables 1 to 4 are shown in FIG.

FIG. 5 is a graph of Comparative Example 1 to Comparative Example 4 and Example 1 to Example 32 in which the ratio I / d between the second moment of area I (cm ⁴ ) and the distance d (cm) is plotted on the horizontal axis. It is the graph which plotted quantity f (ratio with the conventional) as a vertical axis | shaft. Comparative Examples 1 to 4 is shown as point P1 - P4, Embodiments 1 to 32 points for each level of the second moment _{I W} E1-E7, points E8-E16, the points E17-E29 , And points E30 to E32. As shown in the graph of FIG. 5, although the value of the I / d is different for each level of the second moment I _W per wall width 1 m, in each level, the larger the value of the I / d, deflection There was a tendency for the amount f to be reduced.

FIG. 6 shows the ratios I / d between the second moment of area I (cm ⁴ ) and the distance d (cm) on the horizontal axis and the distance on the comparative example 1 to comparative example 4 and example 1 to example 32. It is the graph which plotted the ratio d / W of d (cm) and effective width W (cm) on the vertical axis. In the graph of FIG. 6, points E1 to E32 indicating the example are included in a range of d / W ≦ 4.75 × 10 ⁻⁵ × I / d + 0.085. On the other hand, points P1 to P4 indicating the comparative example 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 equation (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 f.
d / W ≦ 4.75 × 10 ⁻⁵ × I / d + 0.085 (1)

Here, since the area moment of inertia I increases in proportion to the square of the distance d, d / W increases as the area moment of inertia I increases. Also, since the rate of increase of the area moment of inertia I is greater than the rate of increase of the distance d, the larger the area moment of inertia I, the greater the I / d. That is, I / d tends to increase as d / W increases. Therefore, I / d and d / W are indices that correlate with each other in the hat-shaped steel sheet pile. For example, in the comparative examples 1 to 4 (points P1 to P4) in FIG. In the case of hat-shaped steel sheet piles, if the value of d is increased to secure a large second moment of area while widening to make an economical cross section, it is effective to suppress the amount of deflection to an allowable range. There was no criterion on how to determine the width W and the distance d, respectively. In the above study, it was found that it is effective to set d / W to be equal to or less than a predetermined value determined according to I / d from the viewpoint of reducing the amount of deflection f. The relationship between I / d and d / W in the equation (1) is defined as a condition for satisfying the formula (1), and provides a reference for determining the effective width W and the distance d according to the second moment of area I. .

Incidentally, the above-mentioned Examples 1 to 32 are cross-sectional secondary moment _{I W} per wall width 1m of wall linked to the width direction 10000 cm ⁴ / m level, 25000 cm ⁴ / m level, 45000cm ⁴ / m level, and including 50000 cm ⁴ / m level of the hat-shaped steel sheet pile 1, cross-sectional secondary moment I of these hat-shaped steel sheet pile 1 of the single (per sheet) is larger than 9500Cm ^4, and to a smaller extent than 80000Cm ⁴ (9500 cm ⁴ <I <80000 cm ⁴ ).

Furthermore, a hat-shaped steel sheet pile having a so-called thin-walled large cross section with an increased width is preferably formed to have a more compact cross section in consideration of manufacturability. In this respect, among the embodiments discussed above, large moment of inertia I is more 9500Cm ⁴ of a single hat-shaped steel sheet pile 1 (per sheet), and is in the range smaller than 40000cm ^{⁴ (9500cm 4} < I <40000 cm ⁴ ) is more preferable.

FIG. 7 shows that the deflection amount f (ratio to the conventional example) is less than 0.8 among the examples 1 to 32 shown in the graph of FIG. 6, that is, the deflection amount f is 80% of the conventional hat-shaped steel sheet pile. 7 is a graph in which only examples reduced to less than% are extracted. Specifically, Examples 1 to 7, Example 9 to Example 16, and Examples 22 to 32 are extracted. In the graph of FIG. 7, points E1 to E7, E9 to E16, and E22 to E32 indicating the extracted examples are d / W ≦ 1.90 × 10 ⁻⁵ × I / d + 0.111 and I / d ≧ 828 Included in the range. On the other hand, points P1 to P4 indicating the comparative example are in the range of d / W> 1.90 × 10 ⁻⁵ × I / d + 0.111. Therefore, as a condition of the cross-sectional shape of the hat-shaped steel sheet pile 1 that can reduce the deflection amount f to a degree that a practically remarkable effect is seen, specifically, to less than 80% of the conventional hat-shaped steel sheet pile, the following equation ( 2) and Equation (3) can be specified.
d / W ≦ 1.90 × 10 ⁻⁵ × I / d + 0.111 (2)
I / d ≧ 828 (3)

In addition, in order to construct an economical cross section more efficiently than the conventional hat-shaped steel sheet piles, the above-mentioned examination was carried out by setting the effective width W of the hat-shaped steel sheet pile 1 to 90 cm, which is the effective width of the conventional hat-shaped steel sheet pile. The effective width W was 100 cm or more in Examples 1 to 32 because the effective width W was increased in consideration of the enlargement. However, under the conditions of the above equations (1) to (3), the cross section that reduces the amount of deflection as compared with the conventional hat-shaped steel sheet pile is a ratio d / W between the effective width W and the distance d, and the cross section of the distance d and the cross section. Since it is defined only as a relationship with the ratio I / d to the secondary moment I, a cross-sectional shape that can secure a more economical cross-section than a conventional hat-shaped sheet pile, for example, when the effective width W is less than 100 cm Is also considered applicable.

On the other hand, from the viewpoint of economical construction, it is desirable that existing construction machines can be used even if the effective width of hat-shaped steel sheet piles is increased. As for a press-fitting machine which is a kind of construction machine, an effective width of 90 cm (Comparative Example 1 to Comparative Example 4) is widely used, and as a press-fitting machine capable of adapting to a size whose effective width exceeds 90 cm, an effective width of 115 cm or more is used. There is one corresponding to 146.1 cm. That is, 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 as described above, a hat-shaped steel sheet pile having a cross-sectional shape in which horizontal bending deformation generated at the time of driving is effectively reduced is provided. Such a hat-shaped steel sheet pile is formed, for example, by fitting only one of a pair of fitting joints of the hat-shaped steel sheet pile to a fitting joint of a steel sheet pile previously driven. The method is particularly advantageous in a method for manufacturing a steel sheet pile wall including a step of placing the sheet pile in the ground. In such a method for manufacturing a steel sheet pile wall, the construction machine supports the steel sheet pile at a position where one joint of the hat-shaped steel sheet pile is fitted to the joint of the steel sheet pile previously driven. Since the position where the vertical vibration load is applied is eccentric, the hat-shaped steel sheet pile is likely to generate a moment to bend, but by applying the embodiment of the present invention, the bending can be effectively suppressed.

By suppressing the bending deformation of the hat-shaped steel sheet piles, the horizontal vibration of the hat-shaped steel sheet piles on the ground is reduced, and the hat is used in a state in which the construction energy is efficiently used with little loss of the driving energy from the construction machine. The speed of the hat-shaped steel sheet pile penetrating into the ground can be kept high while being transmitted to the shape steel sheet pile, and the fuel-efficient and economical construction of the heavy construction machine becomes possible. In addition, by suppressing the bending 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 accompanying construction can be reduced. Larger construction machines due to the larger cross section of hat-shaped steel sheet piles may increase noise and vibration.However, by suppressing bending deformation of hat-shaped steel sheet piles, it is possible to perform construction with reduced noise and vibration. Become.

Further, by suppressing the bending deformation of the hat-shaped steel sheet pile, the fitting resistance of the steel sheet pile previously driven into the joint can be reduced. Can be reduced, and scraping and welding at the contact surface of the joint can be prevented.

Although the preferred embodiments of the present invention have been described above in detail with reference to the accompanying drawings, the present invention is not limited to such examples. It is obvious that a person having ordinary knowledge in the technical field to which the present invention pertains can conceive various changes or modifications within the scope of the technical idea described in the claims. It is understood that these also belong to the technical scope of the present invention.

1 ... hat-shaped steel sheet pile, 2 ... web, 3A, 3B ... flange, 4A, 4B ... arm, 5A, 5B ... fitting joint, 6 ... vibro-hammer over, C ... centroid, _{E A,} E B _... fitting center .

Claims

A hat-shaped steel sheet pile,
In a cross section orthogonal to the longitudinal direction, a web extending along the width direction on the first side in the depth direction, and both ends in the width direction from both ends in the width direction of the web, and the second side in the depth direction A pair of flanges extending from the respective ends 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. An arm, and a fitting joint formed at an end of each of the pair of arms opposite to the pair of flanges;
A second moment of area I (cm 4 ) of the hat-shaped steel sheet pile in the cross section, a straight line corresponding to the second side surface in the depth direction of the pair of arms in the cross section, and the hat-shaped steel sheet pile A hat shape in which the distance d (cm) between the center of gravity and the effective width W (cm) of the hat-shaped steel sheet pile satisfies the following expression (i), and the effective width W is 100 cm or more: Steel sheet pile.
d / W ≦ 4.75 × 10 −5 × I / d + 0.085 (i)
The hat-shaped steel sheet pile according to claim 1, wherein the second moment of area I, the distance d, and the effective width W satisfy a relationship represented by the following Expressions (ii) and (iii).
d / W ≦ 1.90 × 10 −5 × I / d + 0.111 (ii)
I / d ≧ 828 (iii)
The hat-shaped steel sheet pile according to claim 1 or 2, wherein the effective width W is 115 cm or more.
4. The hat-shaped steel sheet pile according to claim 1, wherein the second moment of area I is larger than 9500 cm 4 and smaller than 80000 cm 4. 5 .
A method for manufacturing a steel sheet pile wall using the hat-shaped steel sheet pile according to any one of claims 1 to 4,
A steel including a step of driving the hat-shaped steel sheet pile into the ground while fitting only one of the fitting joints of the hat-shaped steel sheet pile to the fitting joint of the steel sheet pile previously driven. Manufacturing method of sheet pile wall.