JP2014148798A - Steel sheet pile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a steel sheet pile which is excellent in at least one of processability and economy in comparison with an existing steel sheet pile, and has a suitable shape in a cross section.SOLUTION: In a steel sheet pile, a block resistance formula indicating block resistance being dominant resistance at the installation of the sheet pile 3 is created, the formula is sorted into three formula groups corresponding to three cross shape groups which are stabilized as performance ranges which are regulated with lower limit regions of a processability evaluation index and an economy evaluation index of an existing steel pile as upper limits of the steel sheet pile by using a graph indicating a relationship between a processability evaluation index which indicates a ratio of the block resistance per sheet of a hat-shaped steel sheet pile 1 in the existing steel sheet pile or per pair of Z-shaped steel sheet piles 2 which are hat-shaped in a pair of two sheets with respect to a cross shape, and an economy evaluation index indicating a ratio with respect to a cross shape coefficient of the cross shape per meter of a width in a wall direction at the formation of a wall body in the existing steel sheet pile, and the steel sheet pile has a hat shape or a Z shape having an effective width of 1,270 mm or more at which at least either of values of the processability evaluation index and the economy evaluation index becomes smaller than a value of the existing steel sheet pile.

Description

  The present invention relates to a steel sheet pile used as a retaining wall, revetment, etc. in the field of civil engineering and construction.

Conventionally, regarding steel sheet piles, hat-shaped steel sheet piles (for example, see Patent Documents 1 and 2) and Z-shaped steel sheet piles (for example, see Patent Document 3) are generally known.
Patent Document 1 focuses on minimizing the penetration resistance of the hat-shaped steel sheet pile at the time of placing, and shows a hat-shaped steel sheet pile with improved workability. As a workability evaluation technique for the hat-shaped steel sheet pile, a workability index R created based only on the knowledge of a soil tank test of a steel sheet pile scale model is shown. The workability index R is an evaluation formula calculated by the flange width, web angle, and section height of the hat-shaped steel sheet pile, that is, the product of the tangent of the web angle and the ratio (flange width / section height). It is shown that there is a positive correlation between the workability index R and the penetration resistance. Using the workability index R, a hat-shaped steel sheet pile set to a web angle that minimizes penetration resistance with respect to a predetermined second moment of section is characterized.

Patent Document 2 uses the same evaluation formula as the workability index R as a workability evaluation technique for a hat-shaped steel sheet pile, and shows a hat-shaped steel sheet pile with improved economy and workability. Yes.
Patent Document 3 uses an evaluation formula similar to the workability index R as a workability evaluation technique for a Z-shaped steel sheet pile, and shows a Z-shaped steel sheet pile with improved economy and workability. Yes.
Thus, conventionally, workability is evaluated based on the workability index R as a workability evaluation technique for steel sheet piles.

Japanese Patent No. 3488233 JP 2012-158910 A Japanese Patent No. 4873097

However, the workability index R in the conventional hat-shaped steel sheet pile or Z-shaped steel sheet pile has the following problems.
Since the conventional workability index R is created based only on the knowledge of the model test, the applicability to the workability evaluation of a full-scale steel sheet pile has not been verified. Then, the inventor verified the applicability of the workability evaluation to the full-scale steel sheet pile of the conventional workability index R. That is, a full-scale construction test was performed on the full-size steel sheet pile with a placement depth of 13 m, the workability of the full-size steel sheet pile was evaluated based on the workability index R, and compared with the dynamic resistance of each steel sheet pile. Here, the dynamic resistance is a measured value calculated based on the hydraulic pressure value of the construction machine, etc., and the steel sheet pile with a small dynamic resistance has a small hydraulic value necessary for penetration, that is, the placing resistance is suppressed. It is evaluated as a steel sheet pile with excellent workability.

  As shown in FIG. 25, when the reference steel sheet pile (steel sheet pile (1)) is set to 1, the relationship between the ratio of the workability index R of each steel sheet pile and the ratio of the dynamic resistance is examined. A correlation of the number 0.401 is obtained. This is contrary to the results obtained in the model tests of Patent Documents 1 to 3, and the correlation is low.

  Next, the limit of the application range of the conventional workability index R was investigated in detail. Each steel sheet pile is composed of a first flange and a pair of webs extending from both ends of the first flange, and a pair of second sheets having a joint at the tip extending in parallel with the first flange on the opposite side of the first flange of the web. It is a hat-shaped steel sheet pile made of a flange, and the effective width is 900 mm or less and the effective width is 1270 mm or more when the length between the fitting centers of the pair of joints at the tip of the second flange is the effective width. Steel sheet pile.

When paying attention to the steel sheet pile (4) having an effective width of 900 mm or less, the steel sheet pile (4) has a correlation coefficient between the ratio of the workability index R in FIG. 997, indicating that the correlation is extremely high.
Further, when paying attention to the steel sheet piles (1), (2) and (3) which are steel sheet piles having an effective width of 1270 mm or more, the straight line in which the ratio of the workability index R and the ratio of the dynamic resistance Ru in FIG. The correlation coefficient was 0.349, indicating that the correlation was low.

In other words, the conventional workability index R can be used to evaluate the workability of a full-size steel sheet pile having an effective width of 900 mm or less, and is not applicable to the workability evaluation of a full-size steel sheet pile having an effective width of 1270 mm or more. It was revealed that there is an applicable range related to the effective width for evaluating the workability of large steel sheet piles. That is, it has been clarified that the conventional workability index R has a problem that there is no applicability of workability evaluation of a full-size steel sheet pile with an effective width of 1270 mm or more.
Therefore, there has been a demand for a workability evaluation technique that can reliably apply the workability evaluation of an actual steel sheet pile having an effective width of 1270 mm or more.

  Therefore, regardless of the effective width, it is possible to favorably evaluate the workability with respect to the shape of all regions, and in particular, an actual width of 1270 mm or more that is outside the application range of the conventional workability index R. There was room for improvement in terms of workability evaluation technology that enabled evaluation of workability of large steel sheet piles.

  The present invention has been made in view of the above-described problems, and creates an obstruction resistance formula indicating occlusion resistance that becomes a dominant resistance when placing a steel sheet pile, and uses this occlusion resistance formula to make existing steel It aims at providing the steel sheet pile of the suitable cross-sectional shape excellent in at least one performance among workability and economical efficiency compared with a sheet pile.

In order to achieve the above object, in the steel sheet pile according to the present invention, a hat-shaped or Z-shaped steel sheet pile,
A hat comprising a first flange and a pair of webs extending from both ends of the first flange, and a pair of second flanges having a joint at the tip extending in parallel with the first flange on the opposite side of the first flange of the web In a Z-shaped steel sheet pile comprising a hat-shaped steel sheet pile having a shape and a pair of parallel flanges having joints at opposite ends of the web and opposite ends of the web, a single hat-shaped steel sheet pile or joint is In a Z-shaped steel sheet pile that is a pair of two pieces that are fitted to form a hat,
When the two flanges on the side where the joint is fitted are the first flange and the two flanges on the side where the joint is not fitted are the second flanges in the set of two Z-shaped steel sheet piles, The length between the fitting centers of a pair of joints at the tip is an effective width, the effective width is 1270 mm or more of the hat-shaped steel sheet pile, or a set of two Z-shaped steel sheet piles,
A first flange of a Z-shaped steel sheet pile that is a pair of two hat-shaped steel sheet piles or joints fitted together at the time of placing, and a pair of webs extending from both ends of the first flange; In the area surrounded by, the occlusion that becomes the dominant resistance when placing steel sheet piles along the occlusion area where a higher restraint pressure is generated than the surrounding ground due to overlapping frictional resistance generated at the interface between the steel sheet pile surface and the ground Blocking resistance formula showing resistance is created, and blocking per one set of Z-shaped steel sheet piles per one hat-shaped steel sheet pile in existing steel sheet piles or a pair formed by fitting a joint into a hat shape Expressed the relationship between the workability evaluation index indicating the ratio of the resistance to the cross-sectional area and the economic evaluation index indicating the ratio of the cross-sectional area per 1 m width in the wall direction at the time of wall formation in the existing steel sheet pile. According to the graph, the construction Grouped into three cross-sectional shape groups according to the section modulus Ze discretely classified on the lower limit line of the evaluation index and the economic evaluation index, and the lower limit area of the workability evaluation index and the economic evaluation index of the existing steel sheet pile Three formula groups according to the three cross-sectional shape groups formulated as a performance range that defines the upper limit of the steel sheet pile,
The formula group is
A first formula group corresponding to a range of 1700 ≦ Ze ≦ 2300 cm ³ / m;
A second formula group corresponding to a range of 2300 <Ze ≦ 3400 cm ³ / m;
A third formula group corresponding to a range of 3400 cm ³ / m <Ze;
Sorted into
In the formula group corresponding to the section modulus Ze of the steel sheet pile to be evaluated among the first formula group to the third formula group, at least of the workability evaluation index and the economic evaluation index of the steel sheet pile to be evaluated One value is set so that it may become smaller than the value of any existing steel sheet piles.

  In the present invention, a steel sheet pile having a hat shape or a Z shape, comprising a first flange and a pair of webs extending from both ends of the first flange, the first flange on the opposite side of the web from the first flange. Z formed of a hat-shaped steel sheet pile having a pair of second flanges having a joint at a tip extending in parallel with the web, and a pair of parallel flanges having joints at ends extending in opposite directions to both ends of the web and the web. In a steel sheet pile having a shape, a hat-shaped steel sheet pile or a Z-shaped steel sheet pile that is made into a hat shape by fitting a joint into two pieces, The length between the fitting centers of the pair of joints at the tips of the second flanges when the flanges on both sides of the first flange and the joints not fitted with the second flange are the second flanges. In the hat shape or the two Z-shaped steel sheet piles each having an effective width of 1270 mm or more, and surrounded by a pair of webs extending from both ends of the first flange and the first flange at the time of placing In this area, the friction resistance generated at the interface between the steel sheet pile surface and the ground overlaps, and the blockage resistance becomes the dominant resistance when the steel sheet pile is placed along the blockage area where higher restraint pressure is generated than the surrounding ground. A blockage resistance formula is created, and it becomes possible to evaluate the blockage resistance with respect to the shape of all regions regardless of the effective width based on this blockage resistance formula, and the workability can be evaluated appropriately.

Then, the blockage resistance breakage obtained by the blockage resistance formula per pair of Z-shaped steel sheet piles, which is a pair of the hat-shaped sheet piles in the existing steel sheet piles or by fitting two joints into a hat shape. By a graph showing the relationship between the workability evaluation index indicating the ratio to the area and the economic evaluation index indicating the ratio of the cross-sectional area per 1 m width in the wall direction at the time of wall formation in the existing steel sheet pile, Three cross-sectional shape groups are grouped according to the section modulus Ze discretely classified by the lower limit line of the workability evaluation index and the economic evaluation index, and the workability evaluation index and economic evaluation of the existing steel sheet piles are grouped. Three formula groups are set according to the three cross-sectional shape groups, in which the lower limit area of the index is formulated as a performance range that defines the upper limit of the steel sheet pile, that is, the workability evaluation index and the warp of the steel sheet pile to be evaluated. The workability evaluation index of existing steel sheet piles is compared with the performance range of the workability evaluation index and economic evaluation index formulated by the formula group including the section modulus of the steel sheet pile to be evaluated. It can be evaluated in comparison with an index and an economic evaluation index.
The steel sheet pile to be evaluated is an expression group corresponding to the section modulus Ze of the steel sheet pile to be evaluated among the three expression groups, and the workability evaluation index and the economic evaluation index of the steel sheet pile to be evaluated. It can set so that at least one value may become smaller than the value of any existing steel sheet pile.
Therefore, in this invention, compared with the conventional existing steel sheet pile, the cross-sectional-shaped steel sheet pile excellent in at least one performance among workability | operativity and economical efficiency can be provided.

  In the present invention, a steel sheet pile having a small cross-sectional shape can be evaluated with a workability evaluation index and an economic evaluation index to determine a suitable cross-sectional shape. For example, the evaluation method of the present invention can be applied even to a steel sheet pile having an effective width of 1270 mm or more for which workability could not be evaluated by the conventional evaluation method.

  In the present invention, the hat-shaped steel sheet pile, or the set of two Z-shaped steel sheet piles, wherein the effective width is the length between the fitting centers of a pair of joints at the tip of the second flange. The effective width can be 1270 mm or more.

  In the steel sheet pile according to the present invention, it is preferable that the blocking resistance is obtained from the first flange width, the web angle, and the sectional height of the sectional shape.

  In this case, there exists an advantage which can calculate the said obstruction | occlusion resistance easily from the 1st flange width, web angle, and cross-sectional height of the cross-sectional shape of the steel sheet pile of evaluation object.

  In the steel sheet pile according to the present invention, it is preferable that the formula group is set so as to satisfy a range of (section height / minimum plate thickness) ratio <39. Here, the minimum plate thickness is the minimum plate thickness among the first flange plate thickness, web plate thickness, or second flange plate thickness excluding the joint.

  In this case, the (section height / minimum sheet thickness) ratio, which is a section shape factor having a high correlation with the section deformation at the time of construction, is provided as a constraint value of the formula group, and the (section height / minimum sheet thickness) ratio <39 range Steel sheet pile when the length between the outermost edges in the wall direction at the time of wall body formation from one joint to the other joint at the tip of the second flange of the steel sheet pile is full width The deformation amount of the full width of the steel sheet can be suppressed within the manufacturing tolerance, and the work can be performed as well as the driving speed of the steel sheet pile in a healthy state with almost no change in the full width.

  Further, in the steel sheet pile according to the present invention, the group of formulas holds a hat-shaped steel sheet pile having a hat-shaped cross section or a Z-shaped steel sheet pile that is made into a pair by fitting two joints into a hat shape. The first flange width of the steel sheet pile to do, the geometric constraints determined from the web angle, and the structural constraints defined from the width-thickness ratio according to the steel yield strength for buckling prevention preferable.

  In this case, the cross-sectional shape is determined by the first flange width and web angle of the steel sheet pile for holding a pair of Z-shaped steel sheet piles in a hat shape by fitting a hat-shaped steel sheet pile or joint. Satisfying the constraints, for example, a width-thickness ratio constraint set in the EURO CODE class 3 standard can be used as a structural constraint, and a set of equations that satisfy the buckling performance required by the standard can be set. In addition, a steel sheet pile satisfying structural constraints can be provided.

According to the steel sheet pile of the present invention, a steel sheet pile having a suitable cross-sectional shape excellent in at least one of workability and economic efficiency as compared with any existing steel sheet pile by using an evaluation method considering blocking resistance. Can be provided.
Since it becomes the steel sheet pile in which the obstruction | occlusion resistance which becomes dominant resistance at the time of steel sheet pile driving | running | working was suppressed, a construction load can be reduced and a large construction heavy machine becomes unnecessary and construction cost can be suppressed. In addition, because the ratio of the cross-sectional shape factor (cross-sectional height / minimum sheet thickness), which has a high correlation with the amount of change in the total width that has a large effect on the construction speed, is limited, the full-width deformation of the steel sheet pile at the time of casting is manufactured. The steel sheet pile with a thin and large cross section with high rigidity is economical because it is possible to perform a good construction equivalent to the driving speed of a steel sheet pile in a healthy state that is suppressed within the tolerance and hardly changes in the entire width. However, it is possible to prevent a decrease in the construction yield.
Furthermore, because it satisfies the structural constraints on buckling prevention specified by the width-to-thickness ratio according to the steel yield strength, it can prevent local deformation at the time of placing while being a thin and economical steel sheet pile. A steel sheet pile can be provided.

It is a figure which shows the structure of the Z-shaped steel sheet pile which makes a hat shape by fitting the hat-shaped steel sheet pile or cross-section with a hat shape, and making it into a hat shape. It is a perspective view which shows the structure of the steel sheet pile for demonstrating the placement resistance evaluation type | formula by embodiment of this invention. It is a figure explaining the obstruction | occlusion area | region of a steel sheet pile. Workability evaluation showing the ratio of blockage resistance and cross-sectional area per pair of Z-shaped steel sheet piles in one pair of hat-shaped steel sheet piles in existing steel sheet piles or by fitting two joints into a hat shape shows an exponential (F _occlusion / a), the relationship between economic evaluation index that indicates the ratio of the cross-sectional area and section modulus per width 1m wall direction during wall formation in existing sheet piles (a 0 _/ Ze) It is. It is a figure which shows the relationship between the coefficient a of the quadratic function of the parabola of the obstruction | occlusion area | region, and the web angle of a steel sheet pile cross section. It is a figure which shows the relationship between the function (Hc) / H which consists of the constant c of the quadratic function of the parabola of the obstruction | occlusion area | region, and the formula comprised from a steel sheet pile cross-section factor. It is a figure which shows the relationship between the function (Uk * L) / A _obstruction | _occlusion regarding an obstruction | occlusion area | region, and the formula comprised from a steel sheet pile cross-sectional shape factor. It is a figure which shows the relationship between the placement resistance F by a placement resistance evaluation type | formula, and the placement resistance measured value. It is a figure showing the section modulus of the existing steel sheet pile. It is a figure which shows the flowchart which showed the calculation procedure and calculation conditions of _obstruction | occlusion resistance F _obstruction | _occlusion . It is a figure which shows the 1st formula group of FIG. It is a figure which shows the 2nd formula group of FIG. It is a figure which shows the 3rd type | formula group of FIG. It is a figure which shows the relationship between (cross-sectional height / minimum board thickness) ratio and a full width difference of a steel sheet pile. It is a figure which shows the workability | operativity of a steel sheet pile, Comprising: It is a figure which shows the relationship between placement time and placement depth. It is the figure which showed the relationship between the placement resistance F and dynamic resistance by the placement resistance evaluation type | formula by this Embodiment. It is a figure which shows the cross-sectional shape of the steel sheet pile by 1st Example. It is a figure which shows the result of having evaluated the steel sheet pile of FIG. 17 by the 1st formula group. It is a figure which shows the cross-sectional shape of the steel sheet pile by 2nd Example. It is a figure which shows the result of having evaluated the steel sheet pile of FIG. 19 by the 2nd formula group. It is a figure which shows the cross-sectional shape of the steel sheet pile by 3rd Example. It is a figure which shows the result of having evaluated the steel sheet pile of FIG. 21 by the 3rd type | formula group. It is a figure which shows the cross-sectional shape of the steel sheet pile by 4th Example. It is a figure which shows the result of having evaluated the steel sheet pile of FIG. 23 by the 3rd type | formula group. It is a figure which shows the full-scale construction test result which shows the relationship between the workability parameter | index R by a prior art, and dynamic resistance.

  Hereinafter, the steel sheet pile by embodiment of this invention is demonstrated based on drawing.

The steel sheet pile of the present embodiment is intended for a hat-shaped steel sheet pile 1 made of a hat shape or a Z-shaped steel sheet pile 2 made of a Z shape. The hat-shaped steel sheet pile 1 and the Z-shaped steel sheet pile 2 are collectively referred to as “steel sheet pile 3”.
First, the hat-shaped steel sheet pile 1 shown to Fig.1 (a) is demonstrated. The hat-shaped steel sheet pile 1 includes a first flange 11 and a pair of webs 12 extending from both ends of the first flange 11, and extends parallel to the first flange 11 on the opposite side of the web 12 from the first flange 11. It is a hat-shaped steel sheet pile having a pair of second flanges 13 having a joint at the tip.
The Z-shaped steel sheet pile 2 is a Z-shaped steel sheet pile comprising a web 12 and a pair of parallel flanges 11 and 13 having joints at opposite ends of the web 12 extending in opposite directions. In the case where a pair is formed by fitting a joint into a hat-shaped steel sheet pile, the first flange 11 composed of both flanges on the side where the joint is fitted and the second side on the side where the joint is not fitted And a flange 13.

In the steel sheet pile 3 of the present embodiment, as shown in FIGS. 2 and 3, in the region surrounded by the first flange 11 and a pair of webs 12 extending from both ends of the first flange 11 during placement. Since the frictional resistance generated at the interface between the steel sheet pile surface and the ground overlaps, a closed region in which a higher restraint pressure than the surrounding ground is generated is formed. As shown in FIG. 2, a blocking resistance that becomes a dominant resistance when a steel sheet pile is placed is generated in the blocking region. An obstruction resistance type F _occlusion that indicates the occlusion resistance is newly created and acts on the outer peripheral surface excluding the _{tip of} the tip resistance F acting on the cross-section of the sheet pile _tip and the peripheral surface facing the obstruction area, for which the evaluation method is already known. A placement resistance evaluation formula for determining the placement resistance F, which is the sum of the placement resistance F and the _outer circumference resistance F to be performed, is created. The placement resistance evaluation formula is based on the actual construction test results described later. It has been verified that it is possible to evaluate the workability in the region of the effective width that was outside the application range of the conventional workability index R. In other words, the validity of the workability evaluation of the newly created blockage resistance formula has been confirmed. In order to devise a cross-sectional shape of a hat-shaped steel sheet pile or Z-shaped steel sheet pile that has better workability than existing steel sheet piles, we focus on the blocking resistance, which is the dominant resistance of placing resistance, and block more than existing steel sheet piles. As a workability evaluation index for finding the cross-sectional shape in which the resistance is suppressed, the blocking resistance per one hat-shaped steel sheet pile or the set of two Z-shaped steel sheet piles determined by the blocking resistance formula ( In order to devise a hat-shaped steel sheet pile or a Z-shaped steel sheet pile that is set with a workability evaluation index (F _closed / A) indicating the ratio of the F _closed ) to the cross-sectional area (A), and further excellent in economy. An economic evaluation index (A ₀ / Ze) indicating the ratio of the cross-sectional area A ₀ per 1 m width in the wall direction at the time of wall formation and the section modulus Ze is set, and the workability evaluation index and the economic evaluation index are Graphs expressed as the horizontal axis and vertical axis respectively It is made.

FIG. 4 shows the ratio of the cross-sectional area of the occlusion resistance per one set of Z-shaped steel sheet piles per pair of the hat-shaped steel sheet piles in the existing steel sheet piles or in a hat shape by fitting a joint. The relationship between the workability evaluation index shown and the economic evaluation index (A ₀ / Ze) showing the ratio of the cross-sectional area A ₀ and the section modulus Ze per 1 m width in the wall direction at the time of wall formation in the existing steel sheet pile The graph is shown. Furthermore, the three cross-sectional shape groups according to the section modulus Ze discretely classified by the lower limit line of the workability evaluation index and the economic evaluation index are grouped, and the workability evaluation index and the economic evaluation index of the existing steel sheet piles Three formula groups (first formula group G1, second formula group G2, and third formula group G3 described later) corresponding to the three cross-sectional shape groups formulated as performance ranges that define the lower limit region as the upper limit of the steel sheet pile 3. ) Is set, and in the formula group corresponding to the section modulus Ze of the steel sheet pile 3 to be evaluated, the workability evaluation index (F _blockage / A) and the economic evaluation index (A) of the steel sheet pile 3 to be evaluated ₀ / Ze), at least one value is set to be smaller than any existing steel sheet pile value.

The above-mentioned blocking resistance type will be described more specifically.
As shown in FIGS. 2 and 3 (a), when the steel sheet pile 3 is driven, in the region surrounded by the first flange 11 and the pair of webs 12 extending from both ends of the first flange 11 at the time of driving, There is a blockage region (blockage area A _blockage ) where a high parabolic ground stress occurs along the first flange 11 side and protrudes on the first flange 11 side in a top view. F _blockage occurs.

  This is because the inventor conducted a soil tank test of 1/5, 1 / 7.5, and 1/10 scale steel sheet pile models with different similar laws to the actual steel sheet pile, and the steel after the test. It is based on the result of observing crushed soil particles adhering to the sheet pile and the surrounding ground. The fact that the soil particles are crushed indicates that high stress was generated at that location. As will be described in detail below, as shown in FIG. 3A, the shattered and finely ground soil particles are surrounded by a first flange 11 and a pair of webs 12 extending from both ends of the first flange 11. In the area, it was confirmed that the area along the first flange 11 side and attached to the first flange 11 side in a parabolic shape in a top view formed a closed area (see FIG. 3B). Moreover, it became clear that the formation situation of the adhesion soil of a steel sheet pile, ie, the shape of the parabola B of the obstruction | occlusion area | region, changes with the cross-sectional shape of a steel sheet pile.

Further, when the relation between the coefficient a of the quadratic function of the parabola in the closed region and the distance c from the flange surface to the apex of the parabola and the cross-sectional shape is investigated, the steel sheet pile model with a scale of 1/5 is shown in FIG. as shown in 7, coefficient a quadratic function of the parabola B occlusion region, function consisting distance c from the origin O to the parabola vertex in FIG 3 (a) (H-c ) / H and occlusion area a _closure, It consists of a function of the circumferential length U of the steel sheet pile 3 facing the closed region, the peripheral length L of the parabola B in the closed region, and the ratio k of the friction force between the steel sheet pile and the ground and the ground-ground friction force (U− k × L) / A _obstruction , cross-sectional web angle θ, and (first flange width Wf / cross-sectional height H) ratio have a relationship expressed by equations (1) to (4). It became clear.

Further investigation of the closed region confirmed that the shape of the closed region of the steel sheet pile models having a plurality of different scale ratios in which the cross-sectional shape of the steel sheet pile model is similar has a substantially similar relationship. In other words, when the scale ratio as a representative value is set to 1/5, for example, the shape of the closed region in the steel sheet pile model at a scale of 1/5 has the relationship of the formulas (1) to (4) with the cross-sectional shape factor. The circumferential length U of the steel sheet pile 3 facing the closed region required to calculate the closed resistance described later using these equations (1) to (4) and (U−k × L) / A _blockage can be calculated. And in the case where the cross-sectional shape of the steel sheet pile model is similar, the shape of the closed region is also substantially similar, so the circumferential length U of the steel sheet pile 3 facing the closed region for the full-scale steel sheet pile, (U -k × L) / a 5-fold of the _closure respectively model, evaluates to 1/5-fold is calculated clogging resistance Jitsudai sheet piles. About the validity of the evaluation method of the obstruction resistance of the full-scale steel sheet pile calculated in this way, it is confirmed by the full-scale steel sheet pile construction test result mentioned later.

Moreover, the friction coefficient of the soil and steel sheet pile model specimen is set, and the block resistance evaluated by the block resistance formula described later based on the relational expression of the formulas (1) to (4) from the cross-sectional shape, and the separately evaluated tip end of the sheet pile acting sectional tip resistance F _tip and the outer peripheral resistance F _periphery acting on the outer peripheral surface excluding the peripheral surface facing the closed area, the sum of the pouring resistance evaluation formula and pouring resistance F scale 1/5 of The measured values of the steel sheet pile model were compared. As a result, as shown in FIG. 8, the value of the casting resistance F according to the casting resistance evaluation formula at each depth shows a good agreement with the measured casting resistance value. The validity of modeling can be confirmed.

The placement resistance evaluation formula shown in Formula (5) is composed of a pair of webs extending from both ends of the first flange and the first flange, and the tip of the web extends in parallel with the first flange on the opposite side of the first flange. In a hat-shaped steel sheet pile made up of a pair of second flanges having joints on the web, and a Z-shaped steel sheet pile made up of a pair of parallel flanges having joints at the ends extending in opposite directions to both ends of the web and web, In a Z-shaped steel sheet pile that is a set of two hat-shaped steel sheet piles or joints fitted into a hat shape, the effective width of the hat-shaped or the set of two Z-shaped steel sheet piles is 1270 mm or more In this case, in the set of two Z-shaped steel sheet piles, when both flanges on the side where the joint is fitted are used as the first flange and both flanges on the side where the joint is not fitted are used as the second flange, At the time of installation In a region surrounded by a first flange and a pair of webs extending from both ends of the first flange, a blockage that generates higher restraining pressure than the surrounding ground due to overlapping frictional resistance generated at the interface between the steel sheet pile surface and the ground Blocking resistance F _blockage, which is the dominant resistance when placing steel sheet piles along the region, tip of resistance _tip F (pure cross section tip resistance force) acting on the tip cross section (cross sectional area A) of steel sheet pile 3, It is expressed as the sum of the _outer periphery resistance F acting on the outer peripheral surface excluding the peripheral surface facing the closed region.

As shown in FIG. 1, the closing resistance F _{closing in} the above formula (5) is the first flange width Wf of the cross-sectional shape of the steel sheet pile 3, and the web angle which is a complementary angle of the angle formed by the web 12 and the second flange 13. It is calculated based on θ and the section height H. That is, the block resistance F _block is expressed by equation (6). A _blockage area is A, U is the circumference of the steel sheet pile 3 facing the blockage region, L is the circumference of the parabola B in the blockage region, and (U−k × L) / A _blockage is as shown in FIG. Is calculated from the cross-sectional web angle θ, the cross-sectional height H, and the first flange width Wf according to the equation (3). Note that σ _v is the vertical stress in the closed region and is calculated by the equation (7). In the formula (7), γ is a unit volume weight of soil (for example, 1.8 × 10 ⁻⁸ kN / mm ³ ). Here, σ _v in the equation (7) is equal to or less than the product of the passive earth pressure coefficient and the effective earth pressure determined by the N value and relative density of the target ground.

In the equation (7), μ is a friction coefficient between the soil and the steel sheet pile 3 expressed as μ = tan δ. For example, δ = 15 ° is generally used. Z _v are striking設深degree, [nu is a Rankin Passive earth pressure coefficient ^{(ν = tan 2 (45 °} + φ ° / 2), internal friction angle phi is calculated from the value of N for example, the target ground.

Tip resistance F _tip is (8). Here, α is a bearing force coefficient, A is a cross-sectional area (mm ² ), and N is a tip N value of the target ground. The bearing capacity coefficient α is set to α = 200 in the road earthwork temporary structure guideline (Japan Road Association, March 1999, pages 68 to 70).

Outer peripheral resistance F _periphery is (9). Here, K ₀ is a YAKEY key static pressure coefficient (K ₀ = 1−sin φ), and the internal friction angle φ is calculated from the N value of the target ground, for example.

The _{outer periphery} of the U is the peripheral length of the outer peripheral surface excluding the peripheral surface facing the closed region of the steel sheet pile, that is, the outer peripheral length of the closed region, and the intersection coordinates (X ₀ , Y) of the closed area A shown in FIG. ₀ ) is calculated by simultaneous equations (10) and (11) of the parabola B and the straight line T. The intersection coordinates (X ₀ , Y ₀ ) can be represented by a and c according to equations (12) and (13) according to the formula of the solution, and the circumference of the steel sheet pile 3 facing the closed region. U that is can be calculated by equation (14). Here, X ₀ is a value greater than zero. And the U _outer periphery which is the obstruction | occlusion area | region outer periphery length becomes the length which deducted U which is the perimeter of the steel sheet pile 3 which faces a obstruction | occlusion area | region from the periphery length of the steel sheet pile 3. FIG.

  Note that when the parabola B does not have a solution, such as when the web angle θ, which is a complementary angle of the angle formed by the web 12 and the second flange 13, becomes extremely loose, it means that the closed region does not occur. In that case, what is necessary is just to evaluate that it becomes more than the performance of the existing cross section only about economy. That is, when the inventor evaluated the workability of the existing cross section, the existing cross section has a closed region and a blocking resistance is generated. Since it is clear that it is excellent, it is sufficient to evaluate that only the economic efficiency is equal to or better than the performance of the existing cross section.

Next, the workability evaluation index and the economic evaluation index of the present embodiment will be specifically described.
FIG. 4 shows the blockage resistance F _occlusion and cross-sectional area per Z-shaped steel sheet pile per pair of hat-shaped steel sheet piles in existing steel sheet piles or in a hat shape by fitting a joint. a workability evaluation index indicating a ratio of a (F _occlusion / a), economy shows a cross-sectional area a ₀ and the ratio of the section modulus Ze per 1m wide wall direction during wall formation in existing sheet piles evaluation index ( A ₀ / Ze) is a graph showing the relationship. The unit of F _occlusion / A is (kN / sheet) / (cm ² / sheet), and the unit of A ₀ / Ze is (cm ² / m) / (cm ³ / m).

In the graph of FIG. 4, the horizontal axis is the workability evaluation index (F _occlusion / A), and the smaller this value, the harder it is to occlude and it can be evaluated that the cross section is excellent in workability. The vertical axis is the economic evaluation index (A ₀ / Ze). The smaller this value, the cross-sectional area per 1 m in the wall direction when forming the wall, and the lighter the steel weight, the better the economic efficiency. It can be evaluated that there is. In addition, calculation of blockage resistance F _blockage per set of Z-shaped steel sheet piles per pair of hat-shaped steel sheet piles in existing steel sheet piles or by fitting two joints into a hat shape. A flow chart showing the procedure and calculation conditions is shown in FIG. 10, and the blocking resistance F _blocking is the web angle θ of the cross-sectional shape, the section height H, the first flange width Wf, and the calculation conditions μ = 0.27, ν. = 3.3, γ = 1.8 × 10 ⁻⁸ kN / mm ³ , Z _v = 15000 mm, N value 20 and relative density Dr = 80%.

Here, in the calculation conditions, for example in N value 20 of the target ground to the relative density Dr (%) 80% of ground, are calculated under the conditions Da設the steel sheet pile 3 with striking設深of _{Z v} of 15000mm However, it is not limited to such ground conditions and placement depth. Here, σ _{v in} equation (7) is equal to or less than the product of the passive earth pressure coefficient (ν), the effective soil cover pressure (σ _v0 ) determined by the N value (N) and relative density (Dr) of the target ground. . For the evaluation method of effective soil cover pressure (σ _v0 ) of the target ground, see, for example, the technical standards and explanations of port facilities (Japan Port Association, July 2007, Vol. 320-321) In the case where a relational expression of Dr (%) = 21 × [100 × N / (σ _v0 +70)] ^0.5 is applied, σ _v in the equation (7) is {ν × (441 × N ) / Dr ² −0.7} × 10 ⁻⁴ kN / mm ² or less.

In the graph of FIG. 4, the workability evaluation index of the existing steel sheet pile is grouped into three cross-sectional shape groups according to the section modulus Ze discretely classified by the lower limit line of the workability evaluation index and the economic evaluation index. And three formula groups (first formula group G1, second formula group G2, second formula group corresponding to the three cross-sectional shape groups formulated as a performance range defining the lower limit region of the economic evaluation index as the upper limit of the steel sheet pile 3. A group of three formulas G3) is set. The reason why three formula groups corresponding to the section modulus Ze are set is that the existing steel sheet pile having a section coefficient of 1700 cm ³ / m or more has a section modulus of 1700 ≦ Ze ≦ 2300 cm ³ / This is because it is divided into three groups of m, 2300 <Ze ≦ 3400 cm ³ / m and 3400 cm ³ / m <Ze. In addition, one reason why the section modulus of existing steel sheet piles is roughly divided into three groups is that the group of cross-sectional shapes of existing steel sheet piles, which have different cross-sectional sizes and required rolling capacities during manufacturing, are related to manufacturing efficiency. Further, it can be mentioned that the cross-sectional shape and the required shape-reducing ability at the time of manufacturing are gathered and manufactured in a cross-sectional shape group of three cross-section coefficient classes.
Specifically, the expression group includes a first expression group G1 corresponding to the range of the expression (15), a second expression group G2 corresponding to the range of the expression (16), and a third expression corresponding to the range of the expression (17). It is divided into the formula group G3.

In addition, since the existing steel sheet pile with the largest section modulus Ze is less than about 5500 cm < ³ > / m, the limit line of the 3rd formula group G3 mentioned later is the range of the section modulus of the existing steel sheet pile 3400 <Ze <= 5500 cm < ³ >. It is set under the condition of / m. In addition, when producing the steel sheet pile 3 in which the section modulus Ze exceeds 5500 cm < ³ > / m, the economical performance and the performance of workability should just be compared with the performance range shown by 3rd type | formula group G3. That is, the group of equations corresponding to the steel sheet pile 3 having a section modulus Ze exceeding 3400 cm ³ / m is the third equation group G3.

And each formula group G1, G2, G3 is comprised from the formula which shows a some limit line as shown in FIGS. 11-13, respectively, and these limit lines are each formula group G1-G3 in FIG. It is a line which envelops the lower limit of each of many plots. However, these lines do not include the plot.
Of the limit lines of these formula groups G1, G2, and G3, the lower limit line holds a steel sheet pile having a hat-shaped cross section or a Z-shaped steel sheet pile that is made into a hat shape by fitting two joints into a hat shape. The geometrical constraints determined from the first flange width Wf and the web angle θ of the steel sheet pile 3 and the structural constraints defined by the width-thickness ratio according to the steel yield strength for preventing buckling are set. Yes.
As geometric constraints, the first flange width is Wf> 0 and the web angle is 0 ° <θ <90 °.
Further, as structural constraints, for example, the width-thickness ratio of class 3 shown in EURO CODE (reference: (first flange width Wf / flange plate thickness tf) / ε <66, where ε = 0 when the yield strength is 240 N / m ² .99) is a limitation.

The limit lines (formulas) constituting each formula group described above will be described more specifically.
As shown in FIG. 11, the first expression group G1 includes seven limit lines G1a, G1b, G1c, G1d, G1e, G1f, and G1g.
The first limit line G1a is represented by A ₀ /Ze=0.0766 when 1.40 ≦ (F _occlusion / A) ≦ 1.80, and becomes the upper limit line of the economic evaluation index of the first formula group G1. .
The second limit line G1b is represented by A ₀ /Ze=−0.03×(F _occlusion / A) +0.1186 when 1.00 ≦ (F _occlusion / A) ≦ 1.40, and the first expression group It corresponds to the upper limit line of the economic evaluation index and workability evaluation index of G1.
The third limit line G1c is represented by A ₀ /Ze=0.0884 when 0.11 ≦ (F _occlusion / A) ≦ 1.00, and corresponds to the upper limit line of the economic evaluation index of the first formula group G1 To do. The fourth limit line G1d is expressed by F _occlusion / A ₌ 0.11 in 0.0785 ≦ (A ₀ /Ze)≦0.0884, and is set by geometric constraints or structural constraints. The lower limit line is shown.
The fifth limit line G1e is represented by A ₀ /Ze=−0.0208×(F _occlusion / A) +0.0809 when 0.11 ≦ (F _occlusion / A) ≦ 1.20, and is set from the structural constraints. The lower limit line of the first expression group G1 is shown.
The sixth limit line G1f is represented by A ₀ /Ze=0.0560 when 1.20 ≦ (F _occlusion / A) ≦ 1.80, and represents the lower limit line of the first expression group G1 set from the structural constraints. Show.
The seventh limit line G1g is represented by F _occlusion / A ₌ 1.8 in 0.0560 ≦ (A ₀ /Ze)≦0.0766, and corresponds to the upper limit line of the workability evaluation index of the first formula group G1 To do.

As shown in FIG. 12, the second expression group G2 is composed of eight limit lines G2a, G2b, G2c, G2d, G2e, G2f, G2g, and G2h.
The first limit line G2a is represented by A ₀ /Ze=0.0713 when 1.04 ≦ (F _occlusion / A) ≦ 1.20, and corresponds to the upper limit line of the economic evaluation index of the second formula group G2. To do.
The second limit line G2b is represented by A ₀ /Ze=−0.0077×F _occlusion / A ₊ 0.0793 when 0.89 ≦ (F _occlusion / A) ≦ 1.04, and the economy of the second equation group G2 It corresponds to the upper limit line of the workability evaluation index and the workability evaluation index.
The third limit line G2c is represented by A ₀ /Ze=−0.0306×F _occlusion / A ₊ 0.0997 when 0.66 ≦ (F _occlusion / A) ≦ 0.89, and the economy of the second equation group G2 It corresponds to the upper limit line of the workability evaluation index and the workability evaluation index.
The fourth limit line G2d is represented by A ₀ /Ze=0.0795 when 0.12 ≦ (F _occlusion / A) ≦ 0.66, and corresponds to the upper limit line of the economic evaluation index of the second formula group G2. To do.
The fifth limit line G2e is expressed by F _occlusion / A ₌ 0.12 in 0.0633 ≦ (A ₀ /Ze)≦0.0795, and is set in the second expression group G2 set from the geometric constraint or the structural constraint. The lower limit line is shown.
The sixth limit line G2f is represented by A ₀ /Ze=−0.0225×F _occlusion / A ₊ 0.066 when 0.12 ≦ (F _occlusion / A) ≦ 0.85, and is set from the structural constraints. The lower limit line of group 2 group G2 is shown.
The seventh limit line G2g is represented by A ₀ /Ze=0.0469 when 0.85 ≦ (F _occlusion / A) ≦ 1.20, and represents the lower limit line of the second expression group G2 set from the structural constraints. Show.
The eighth limit line G2h is represented by F _blockage / A ₌ 1.2 in 0.0469 ≦ (A ₀ /Ze)≦0.0713, and corresponds to the upper limit line of the workability evaluation index of the second formula group G2. To do.

As shown in FIG. 13, the third expression group G3 is composed of six limit lines G3a, G3b, G3c, G3d, G3e, and G3f.
The first limit line G3a is represented by A ₀ /Ze=0.0602 when 0.52 ≦ (F _occlusion / A) ≦ 0.75, and corresponds to the upper limit line of the economic evaluation index of the third formula group G3 To do.
The second limit line G3b is represented by A ₀ /Ze=−0.025×F _occlusion / A ₊ 0.0732 when 0.36 ≦ (F _occlusion / A) ≦ 0.52, and the economy of the third equation group G3 It corresponds to the upper limit line of the workability evaluation index and the workability evaluation index.
The third limit line G3c is represented by A ₀ /Ze=0.0642 when 0.13 ≦ (F _occlusion / A) ≦ 0.36, and corresponds to the upper limit line of the economic evaluation index of the third formula group G3 To do.
The fourth limit line G3d is expressed by F _occlusion / A = 0.13 when 0.0506 ≦ (A ₀ /Ze)≦0.0642, and is set in the third group of equations G3 set from the geometric constraint or the structural constraint. The lower limit line is shown.
The fifth limit line G3e is represented by A ₀ /Ze=−0.0237×F _occlusion / A ₊ 0.0538 when 0.13 ≦ (F _occlusion / A) ≦ 0.75, and is set based on the structural constraints. The lower limit line of group 3 group G3 is shown.
The sixth limit line G3f is represented by F _occlusion / A = 0.75 when 0.0360 ≦ (A ₀ /Ze)≦0.0602, and corresponds to the upper limit line of the workability evaluation index of the third formula group G3 To do.

Further, FIG. 14 shows a ratio (H / t) of (section height H / minimum sheet thickness t) which is a section shape factor having a high correlation with the section deformation at the time of construction, and was obtained in an actual construction test. It is data. Since a full-scale steel sheet pile may be constructed by holding the first flange at the site, an eccentric external force may act on the steel sheet pile, and the steel sheet pile cross section may be deformed. When the steel sheet pile cross-section is deformed, the placement resistance may increase according to the change in the cross-sectional shape. Then, when the relationship between cross-sectional deformation and various shape factors was investigated based on the actual construction test results of a plurality of steel sheet piles, when H / t exceeded 39, there was a relationship that a cross-sectional deformation exceeding 10 mm was caused in the total width difference. It became clear that there was. That is, it has been clarified that when the JIS production tolerance is 10 mm in total width and H / t exceeds 39, a large cross-sectional deformation exceeding the JIS production tolerance occurs. From this knowledge, if the ratio of the cross-sectional height H to the minimum flange thickness t of the first flange plate thickness, web plate thickness or second flange plate thickness exceeds 39, a large deformation exceeding 10 mm of the JIS production tolerance occurs. It is desirable that the constraint value of the ratio between the cross-sectional height H and the minimum plate thickness t is less than 39.
The data shown in FIG. 14 and the value of the constraint value 39 of H / t are for a standard ground where a steel sheet pile having an N value of less than 50 on the target ground can be placed without an auxiliary construction method such as a water jet. Therefore, although the constraint value varies depending on the type and strength of the ground, using this index with the N value 50 of the target ground as the upper limit can cover normal steel sheet pile driving.

  FIG. 15 compares the construction time of the steel sheet pile (5) with H / t <39 shown in FIG. 14 and the steel sheet pile (6) with H / t = 39. As a result, the steel sheet pile (6) has a longer placement time than the steel sheet pile (5) as the placement depth becomes 7 m or less, and is about twice as long as the steel sheet pile (5) by the 15 m placement. It can be confirmed that the workability is significantly reduced. Therefore, good workability can be secured by setting H / t to less than 39.

Next, it is verified that the placement resistance F by the placement resistance evaluation formula created in the present embodiment can be quantitatively evaluated from the viewpoint of workability of a full-size steel sheet pile as shown in FIG. ing.
FIG. 16 shows the ratio of the placing resistance F and the ratio of the dynamic resistance Ru according to the placing resistance evaluation formula according to the present embodiment of each steel sheet pile when the steel sheet pile (steel sheet pile (1)) as the reference is 1. FIG. Each steel sheet pile in FIG. 16 includes a steel sheet pile having an effective width of 900 mm or less and an effective width of 1270 mm or more. In this case, the correlation coefficient between the ratio of the placement resistance F and the ratio of the dynamic resistance Ru according to the placement resistance evaluation formula is 0.912, and the placement resistance evaluation formula is the shape of all regions regardless of the effective width. On the other hand, it is possible to suitably evaluate the workability, that is, it is possible to evaluate the workability of a full-scale steel sheet pile having an effective width of 1270 mm or more that is outside the scope of application of the conventional workability index R. I can confirm.

Next, the effect | action of the steel sheet pile mentioned above is demonstrated in detail based on drawing. As shown in FIGS. 2 and 3, in the present embodiment, in the steel sheet pile having a hat shape or a Z shape, both ends of the first flange 11 and the first flange 11 at the time of placement shown in the above formula (6). In a region surrounded by a pair of webs 12 extending from the steel sheet pile, the friction resistance generated at the interface between the steel sheet pile surface and the ground overlaps, so that the steel sheet pile is driven along the closed region where a higher restraint pressure is generated than the surrounding ground. The blockage resistance formula that uses the blockage resistance F _blockage, which is a typical resistance, as a calculation item is created, and the blockage resistance F _blockage is evaluated based on this blockage resistance equation. It is possible to suitably evaluate the workability with respect to the shape of, and in particular, the length between the fitting centers of a pair of joints at the tip of the second flange that is outside the scope of application of the conventional workability index R Is the effective width and the front Effective width is possible workability Evaluation of Full Scale sheet piles over 1270 mm.

Then, using the closing resistor F _closed, a closing resistor F _occlusion of Z-shaped steel sheet pile per set comprising a set of two you hat shape by the hat-shaped steel sheet pile fitted with one or per joint together a workability evaluation index that indicates the ratio of the cross-sectional area a, graph the relationship between the economic evaluation index indicating the cross-sectional area a ₀ and the ratio of the section modulus Ze per 1m wide wall direction during wall formation in existing sheet piles By grouping the cross-sectional shape groups according to the section modulus Ze, the first expression group G1 to the third expression group G3 sorted according to the section modulus Ze described above are provided, and this is the performance range of the steel sheet pile 3 It can be.

Therefore, it becomes possible to set the limit area | region of a workability evaluation index and an economical evaluation index by these formula groups G1, G2, and G3. That is, the workability evaluation index and the economic evaluation index of the steel sheet pile 3 to be evaluated are the workability evaluation index and economic evaluation formulated by the formula group G including the section modulus Ze of the steel sheet pile 3 to be evaluated. In the limit area of the index, it can be evaluated in comparison with the workability evaluation index and the economic evaluation index of the existing steel sheet pile. The steel sheet pile to be evaluated can be set so that at least one of the workability evaluation index and the economic evaluation index is smaller than the value of any existing steel sheet pile.
Therefore, compared with the conventional existing steel sheet pile, the steel sheet pile of the cross-sectional shape excellent in at least one performance among workability and economical efficiency can be provided.

  Further, in the present embodiment, in the steel sheet pile having a hat shape or a Z shape, a steel sheet pile having a suitable cross-sectional shape is evaluated by using a workability evaluation index and an economic evaluation index for a steel sheet pile having a small cross-sectional shape. Can be determined. For example, when the effective width is the length between the fitting centers of a pair of joints at the tip of the second flange, which is outside the scope of the conventional workability index R, the effective width is 1270 mm or more. Even if it is a large steel sheet pile, this evaluation method can be applied.

  Further, in the present embodiment, the (section height / minimum thickness) ratio, which is a sectional shape factor having a high correlation with the section deformation at the time of construction, is provided as a constraint value of the formula group, and (section height / minimum thickness) By setting it as the steel sheet pile which becomes the range of ratio <39, the construction which suppressed the deformation amount of the full width of the steel sheet pile within the JIS production tolerance can be performed.

Moreover, in this Embodiment, as shown to said (6) Formula, obstruction | occlusion resistance F _{obstruction | occlusion} is easy from the 1st flange width Wf of the cross-sectional shape of the steel sheet pile to be evaluated, web angle (theta), and cross-section height H. There is an advantage that can be calculated.

  Furthermore, in the present embodiment, for example, a hat shape in which the cross-sectional shape determined from the first flange width of the steel sheet pile and the web angle is a hat shape with the width-thickness ratio constraint set in the standard of class 3 of EURO CODE as a structural constraint. It is possible to set a formula group that satisfies the geometric constraints for holding a pair of Z-shaped steel sheet piles by fitting two steel sheet piles or joints into a hat shape, satisfying the performance required by the standard A steel sheet pile having a cross-sectional shape can be provided.

  In the steel sheet pile according to the present embodiment described above, a steel sheet pile having a suitable cross-sectional shape excellent in at least one of workability and economic efficiency as compared with existing steel sheet piles by using an evaluation method in consideration of blocking resistance. Can be provided.

  Next, examples for supporting the effect of the steel sheet pile according to the above-described embodiment will be described below.

(First embodiment)
In the first embodiment, the steel sheet piles included in the first formula group G1 (see FIG. 18) in which the section modulus Ze of the steel sheet pile shown in FIG. 17 is in the range of 1700 ≦ Ze ≦ 2300 cm ³ / m ((15) formula). It is an example. In this 1st Example, it is a Z-shaped steel sheet pile which makes a pair by fitting two joints and each dimension is shown in FIG. In addition, as shown in FIG. 18, the lower limit of the workability evaluation index (F _occlusion / A) in the existing steel sheet pile of the first formula group G1 is 1.4, and the economic evaluation index (A ₀ / Ze) The lower limit is 0.0766.

As shown in Table 1, the steel sheet pile of the first example is included in the first formula group G1 because the section modulus Ze is 2134 cm ³ / m, and each limit line G1a to G1g of the first formula group G1. (See FIG. 11).
As shown in FIG. 18, the workability evaluation index (F _occlusion / A) of the steel sheet pile of the first example set to the cross-sectional shape of Table 1 is 0.94, and the economic evaluation index (A ₀ / Ze) Was 0.0734. In other words, the steel sheet pile of the first example is smaller than the lower limit (0.0766) of the economic evaluation index (A ₀ / Ze) of the existing steel sheet pile in terms of economy, and is compared with the existing steel sheet pile of the first example. The performance is improved by about 4%. Moreover, in the workability, among the existing steel sheet piles, the economic evaluation index (A ₀ / Ze) is the lower limit value of the workability evaluation index (F _occlusion / A) of the existing steel sheet pile, which is the lower limit value (0.0766). .40, the performance of the first embodiment with respect to the existing steel sheet pile is improved by about 33%.

Moreover, the workability evaluation index (F _blockage / A) of the steel sheet pile of the first example is 0.94, and the steel sheet pile of the first example and the workability evaluation index (F _blockage / A) are the same (0. 94) When compared with the lower limit (0.0884) of the economic evaluation index (A ₀ / Ze) of the existing steel sheet pile, the performance of the first embodiment with respect to the existing steel sheet pile is improved by about 17%.

(Second embodiment)
The second embodiment is an example of a steel sheet pile included in the second formula group G2 (see FIG. 20) in which the section modulus Ze shown in FIG. 19 is in the range of 2300 <Ze ≦ 3400 cm ³ / m (equation (16)). . In this 2nd Example, it is a Z-shaped steel sheet pile which makes a pair by fitting a joint and making it into a hat shape, and each dimension is shown in FIG. In addition, as shown in FIG. 20, the lower limit value of the economical evaluation index (A ₀ / Ze) of the existing steel sheet pile compared with this cross-sectional shape is 0.0713, and the economic evaluation index (A ₀ / Ze) However, the lower limit of the workability evaluation index (F _occlusion / A) of the existing steel sheet pile at 0.0713 is 1.04.

As shown in Table 2, the steel sheet pile of the second example is included in the second formula group G2 because the section modulus Ze is 3057 cm ³ / m, and each limit line G2a to G2h of the second formula group G2 (See FIG. 12).
As shown in FIG. 20, the workability evaluation index (F _occlusion / A) of the steel sheet pile of the second example set to the cross-sectional shape of Table 2 is 0.68, and the economic evaluation index (A ₀ / Ze) Was 0.0643. That is, the steel sheet pile of the second embodiment is smaller than the lower limit (0.0713) of the economic evaluation index (A ₀ / Ze) of the existing steel sheet pile in terms of economy, and is compared with the existing steel sheet pile of the second embodiment. The performance is improved by about 10%. Moreover, in workability, among the existing steel sheet piles, 1 is the lower limit value of the workability evaluation index (F _blockage / A) of the existing steel sheet piles where the economic evaluation index (A ₀ / Ze) is the lower limit value (0.0713). .04, the performance of the second embodiment with respect to the existing steel sheet pile is improved by approximately 35%.

Moreover, the workability evaluation index (F _blockage / A) of the steel sheet pile of the second example is 0.68, and the steel sheet pile of the second example and the workability evaluation index (F _blockage / A) are the same (0. 68), compared with the lower limit (0.0789) of the economic evaluation index (A ₀ / Ze) of the existing steel sheet pile, the performance of the second embodiment with respect to the existing steel sheet pile is improved by about 19%.

(Third embodiment)
The third embodiment is an example of a steel sheet pile included in the third formula group G3 (see FIG. 22) in which the section modulus Ze shown in FIG. 21 is in the range of 3400 cm ³ / m <Ze shown in the formula (17). The third embodiment is a Z-shaped steel sheet pile which is a set of two pieces fitted with a joint to form a hat shape, and the dimensions are shown in FIG. In the third embodiment, H / t> 39. In addition, as shown in FIG. 22, the lower limit value of the economic evaluation index (A ₀ / Ze) of the existing steel sheet pile compared with this cross-sectional shape is 0.0602, and the economic evaluation index (A ₀ / Ze) However, the lower limit of the workability evaluation index (F _occlusion / A) of the existing steel sheet pile at 0.0602 is 0.52.

As shown in Table 3, the steel sheet pile of the third embodiment has a section modulus Ze of 4466 cm ³ / m, and thus is included in the third formula group G3 and each limit line G3a to G3f of the third formula group G3. (See FIG. 13).
As shown in FIG. 22, the workability evaluation index (F _occlusion / A) of the steel sheet pile of the third example set to the cross-sectional shape of Table 3 is 0.49, and the economic evaluation index (A ₀ / Ze) Was 0.0507. In other words, the steel sheet pile of the third embodiment is smaller than the lower limit (0.0602) of the economic evaluation index (A ₀ / Ze) of the existing steel sheet pile in terms of economy, and is compared with the existing steel sheet pile of the third embodiment. The performance is improved by about 16%. Moreover, in workability, among the existing steel sheet piles, ₀ is the lower limit value of the workability evaluation index (F _occlusion / A) of the existing steel sheet pile in which the economic evaluation index (A ₀ / Ze) is the lower limit value (0.0602). .52, the performance of the third embodiment relative to the existing steel sheet pile is improved by about 5%.

Moreover, the workability evaluation index (F _blockage / A) of the steel sheet pile of the third example is 0.49, and the steel sheet pile of the third example and the workability evaluation index (F _blockage / A) are the same 0.49. When compared with the lower limit (0.0609) of the economic evaluation index (A ₀ / Ze) of the existing steel sheet pile, the performance of the third embodiment with respect to the existing steel sheet pile is improved by about 17%.

(Fourth embodiment)
The fourth embodiment is an example of a steel sheet pile included in the third formula group G3 (see FIG. 24) in which the section modulus Ze shown in FIG. 23 is in the range of 3400 cm ³ / m <Ze shown in the formula (17). In this 4th Example, it is a Z-shaped steel sheet pile which makes a pair by fitting two joints and each dimension is shown in FIG. In the fourth embodiment, a constraint condition of H / t <39 is provided. In addition, as shown in FIG. 24, the lower limit value of the economical evaluation index (A ₀ / Ze) of the existing steel sheet pile compared with this cross-sectional shape is 0.0602, and the economic evaluation index (A ₀ / Ze) However, the lower limit of the workability evaluation index (F _occlusion / A) of the existing steel sheet pile at 0.0602 is 0.52.

As shown in Table 4, the steel sheet pile of the fourth example is included in the third formula group G3 because the section modulus Ze is 4916 cm ³ / m, and each of the limit lines G3a to G3f of the third formula group G3. (See FIG. 13).
As shown in FIG. 24, the workability evaluation index (F _occlusion / A) of the steel sheet pile of the fourth example set to the cross-sectional dimensions of Table 4 is 0.43, and the economic evaluation index (A ₀ / Ze) Was 0.0562. In other words, the steel sheet pile of the fourth example is smaller than the lower limit (0.0602) of the economic evaluation index (A ₀ / Ze) of the existing steel sheet pile in terms of economy, and is compared with the existing steel sheet pile of the fourth example. The performance is improved by about 7%. Moreover, in terms of workability, the workability evaluation index (F _occlusion / A) of the steel sheet pile of the fourth example in which the economic evaluation index (A ₀ / Ze) is the lower limit (0.0602) among the existing steel sheet piles. It is smaller than the lower limit of 0.52, and the performance of the fourth embodiment with respect to the existing steel sheet pile is improved by about 18%.

Moreover, the workability evaluation index (F _blockage / A) of the steel sheet pile of the fourth example is 0.43, and the steel sheet pile of the fourth example and the workability evaluation index (F _blockage / A) are the same 0.43. When compared with the lower limit (0.0625) of the economic evaluation index (A ₀ / Ze) of the existing steel sheet pile, the performance of the third embodiment with respect to the existing steel sheet pile is improved by about 10%.

As mentioned above, although embodiment of the steel sheet pile by this invention was described, this invention is not limited to said embodiment, In the range which does not deviate from the meaning, it can change suitably.
For example, in the above-described embodiment, the range of (section height / minimum plate thickness) ratio <39 is set, but it is not limited to providing such a restriction.

  In addition, it is possible to appropriately replace the components in the above-described embodiments with known components without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 1 Hat-shaped steel sheet pile 2 Z-shaped steel sheet pile 3 Steel sheet pile 11 1st flange 12 Web 13 2nd flange G1 1st type group G2 2nd type group G3 3rd type group

Claims (6)

A steel sheet pile made of a hat shape or a Z shape,
A hat comprising a first flange and a pair of webs extending from both ends of the first flange, and a pair of second flanges having a joint at the tip extending in parallel with the first flange on the opposite side of the first flange of the web A hat-shaped steel sheet pile in shape,
In a Z-shaped steel sheet pile consisting of a pair of parallel flanges having joints at opposite ends of the web and opposite ends of the web, a hat-shaped steel sheet pile or joint is fitted into a hat shape. In the Z-shaped steel sheet pile that is a set of two,
When the two flanges on the side where the joint is fitted are the first flange and the two flanges on the side where the joint is not fitted are the second flange in the set of two Z-shaped steel sheet piles,
The length between the fitting centers of a pair of joints at the tip of the second flange is an effective width, and the effective width is 1270 mm or more of the hat-shaped steel sheet pile or the set of two Z-shaped steel sheet piles. And
A first flange of a Z-shaped steel sheet pile that is a pair of two hat-shaped steel sheet piles or joints fitted together at the time of placing, and a pair of webs extending from both ends of the first flange; In the area surrounded by, the occlusion that becomes the dominant resistance when placing steel sheet piles along the occlusion area where a higher restraint pressure is generated than the surrounding ground due to overlapping frictional resistance generated at the interface between the steel sheet pile surface and the ground Occlusion resistance formula showing resistance is created,
Workability showing the ratio of cross-sectional resistance to the cross-sectional area of one set of Z-shaped steel sheet piles per pair of hat-shaped steel sheet piles in existing steel sheet piles or two pieces made by fitting joints into a hat shape. Evaluation index,
An economic evaluation index indicating the ratio of the cross-sectional area per 1 m width in the wall direction at the time of wall formation in the existing steel sheet pile to the section modulus;
Are grouped into three cross-sectional shape groups according to the section modulus Ze discretely classified by the lower limit line of the workability evaluation index and the economic evaluation index, and the construction of the existing steel sheet pile Three formula groups according to the three cross-sectional shape groups formulated as the performance range that defines the upper limit of the steel sheet pile as the lower limit region of the property evaluation index and economic evaluation index is set,
The formula group is
A first formula group corresponding to a range of 1700 ≦ Ze ≦ 2300 cm ³ / m;
A second formula group corresponding to a range of 2300 <Ze ≦ 3400 cm ³ / m;
A third formula group corresponding to a range of 3400 cm ³ / m <Ze;
Sorted into
In the first formula group, at least one of the workability evaluation index and the economic evaluation index of the steel sheet pile to be evaluated is set to be smaller than any existing steel sheet pile. Steel sheet pile to be used. A steel sheet pile made of a hat shape or a Z shape,
A hat comprising a first flange and a pair of webs extending from both ends of the first flange, and a pair of second flanges having a joint at the tip extending in parallel with the first flange on the opposite side of the first flange of the web A hat-shaped steel sheet pile in shape,
In a Z-shaped steel sheet pile consisting of a pair of parallel flanges having joints at opposite ends of the web and opposite ends of the web, a hat-shaped steel sheet pile or joint is fitted into a hat shape. In the Z-shaped steel sheet pile that is a set of two,
When the two flanges on the side where the joint is fitted are the first flange and the two flanges on the side where the joint is not fitted are the second flange in the set of two Z-shaped steel sheet piles,
The length between the fitting centers of a pair of joints at the tip of the second flange is an effective width, and the effective width is 1270 mm or more of the hat-shaped steel sheet pile or the set of two Z-shaped steel sheet piles. And
A first flange of a Z-shaped steel sheet pile that is a pair of two hat-shaped steel sheet piles or joints fitted together at the time of placing, and a pair of webs extending from both ends of the first flange; In the area surrounded by, the occlusion that becomes the dominant resistance when placing steel sheet piles along the occlusion area where a higher restraint pressure is generated than the surrounding ground due to overlapping frictional resistance generated at the interface between the steel sheet pile surface and the ground Occlusion resistance formula showing resistance is created,
Workability showing the ratio of cross-sectional resistance to the cross-sectional area of one set of Z-shaped steel sheet piles per pair of hat-shaped steel sheet piles in existing steel sheet piles or two pieces made by fitting joints into a hat shape. Evaluation index,
An economic evaluation index indicating the ratio of the cross-sectional area per 1 m width in the wall direction at the time of wall formation in the existing steel sheet pile to the section modulus;
Are grouped into three cross-sectional shape groups according to the section modulus Ze discretely classified by the lower limit line of the workability evaluation index and the economic evaluation index, and the construction of the existing steel sheet pile Three formula groups according to the three cross-sectional shape groups formulated as the performance range that defines the upper limit of the steel sheet pile as the lower limit region of the property evaluation index and economic evaluation index is set,
The formula group is
A first formula group corresponding to a range of 1700 ≦ Ze ≦ 2300 cm ³ / m;
A second formula group corresponding to a range of 2300 <Ze ≦ 3400 cm ³ / m;
A third formula group corresponding to a range of 3400 cm ³ / m <Ze;
Sorted into
In the second formula group, at least one of the workability evaluation index and the economic evaluation index of the steel sheet pile to be evaluated is set to be smaller than any existing steel sheet pile. Steel sheet pile to be used. A steel sheet pile made of a hat shape or a Z shape,
A hat comprising a first flange and a pair of webs extending from both ends of the first flange, and a pair of second flanges having a joint at the tip extending in parallel with the first flange on the opposite side of the first flange of the web A hat-shaped steel sheet pile in shape,
In a Z-shaped steel sheet pile consisting of a pair of parallel flanges having joints at opposite ends of the web and opposite ends of the web, a hat-shaped steel sheet pile or joint is fitted into a hat shape. In the Z-shaped steel sheet pile that is a set of two,
When the two flanges on the side where the joint is fitted are the first flange and the two flanges on the side where the joint is not fitted are the second flange in the set of two Z-shaped steel sheet piles,
The length between the fitting centers of a pair of joints at the tip of the second flange is an effective width, and the effective width is 1270 mm or more of the hat-shaped steel sheet pile or the set of two Z-shaped steel sheet piles. And
A first flange of a Z-shaped steel sheet pile that is a pair of two hat-shaped steel sheet piles or joints fitted together at the time of placing, and a pair of webs extending from both ends of the first flange; In the area surrounded by, the occlusion that becomes the dominant resistance when placing steel sheet piles along the occlusion area where a higher restraint pressure is generated than the surrounding ground due to overlapping frictional resistance generated at the interface between the steel sheet pile surface and the ground Occlusion resistance formula showing resistance is created,
Workability showing the ratio of cross-sectional resistance to the cross-sectional area of one set of Z-shaped steel sheet piles per pair of hat-shaped steel sheet piles in existing steel sheet piles or two pieces made by fitting joints into a hat shape. Evaluation index,
An economic evaluation index indicating the ratio of the cross-sectional area per 1 m width in the wall direction at the time of wall formation in the existing steel sheet pile to the section modulus;
Are grouped into three cross-sectional shape groups according to the section modulus Ze discretely classified by the lower limit line of the workability evaluation index and the economic evaluation index, and the construction of the existing steel sheet pile Three formula groups according to the three cross-sectional shape groups formulated as the performance range that defines the upper limit of the steel sheet pile as the lower limit region of the property evaluation index and economic evaluation index is set,
The formula group is
A first formula group corresponding to a range of 1700 ≦ Ze ≦ 2300 cm ³ / m;
A second formula group corresponding to a range of 2300 <Ze ≦ 3400 cm ³ / m;
A third formula group corresponding to a range of 3400 cm ³ / m <Ze;
Sorted into
In the third formula group, at least one of the workability evaluation index and the economic evaluation index of the steel sheet pile to be evaluated is set to be smaller than any existing steel sheet pile. Steel sheet pile to be used.   The steel sheet pile according to any one of claims 1 to 3, wherein the blockage resistance formula is obtained from the first flange width, the web angle, and the cross-sectional height of the cross-sectional shape.   The formula group satisfies a range in which the ratio of the cross-sectional height to the minimum plate thickness that is the minimum plate thickness of the first flange plate thickness, the web plate thickness, or the second flange plate thickness is less than 39. The steel sheet pile according to any one of claims 1 to 4, wherein the steel sheet pile is set to be performed. The formula group is
The cross-sectional shape is determined from the first flange width and web angle of the steel sheet pile for holding a pair of hat-shaped steel sheet piles or joints fitted with a hat-shaped Z-shaped steel sheet pile. Geometric constraints,
Structural constraints stipulated from the width-thickness ratio according to the steel yield strength to prevent buckling,
Is set, The steel sheet pile according to any one of claims 1 to 5.