JPH07119142A - Steel sheet pile and steel continuous wall - Google Patents

Abstract

PURPOSE:To increase the separation resistance between steel sheet piles and concrete, in a steel continuous wall constituted of steel sheet piles and concrete. CONSTITUTION:A steel sheet pile 1 is made of a steel plate 2 with a plurality of ribs 3 (special rib) having dovetail-form sections at both sides thereof. The maximum width of the rib 3 or the length 31 of the outer side of the steel plate 2 is larger than the width of the root of rib 3 at the steel plate 2 or the inside length 32. A steel continuous wall is constituted of the steel sheet piles 1 erected in a groove excavated in the ground and concrete placed in the groove. Accordingly, the steel plate unified with the concrete and the resistance against separation thereof is increased and hence, the sectional area can be reduced and the wall thickness can be lessened. This pile dispenses with construction yards at site and connecting devices with post-cast concrete like dowels can be eliminated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steel continuous wall which constitutes a continuous concrete underground wall such as a temporary earth retaining wall, a main body underground wall, an underground tank wall, a steel segment, a rigid foundation or an impermeable wall in construction work. The present invention relates to a wall and a steel sheet pile used for the wall.

[0002]

2. Description of the Related Art Reinforcing bar baskets 9 as shown in FIGS. 9 to 12 have been conventionally used for the construction of continuous concrete underground walls. However, as shown in FIG.
When constructing a concrete underground wall by reinforcing the inside of the wall with a reinforcing cage, there are many problems as described below. Since the rebar cage is assembled locally, a large construction yard for it is necessary. Especially in construction in urban areas, it is often difficult to secure the work space. Since the rebar cage has a low cross-sectional rigidity, the required cross-sectional area is large and the wall thickness is large in order to increase the composite cross-sectional strength with concrete.

On the other hand, a method of using a steel sheet pile in place of the above-mentioned reinforcing bar cage is used as a construction means for a continuous concrete underground wall. That is, a groove is excavated in the ground, a steel sheet pile is built into the excavated groove as shown in FIG. 14, concrete is placed in the groove, and a continuous wall composed of concrete and steel sheet pile in the ground ( Hereinafter, "steel wall" will be constructed. In FIG. 14, 8 is a steel wall, 10 is a shear connector forming a joint with post-cast concrete, 5 is concrete, 15 is a steel sheet pile made of ordinary steel plate, 6 is post-cast concrete, 11 is stud weld , 12 are studs.

Conventionally, as steel sheet piles used for steel connecting walls, as described in JP-A-55-68921, JP-A-55-165320 and JP-A-4-19076, 1
5 to 18 have been proposed.

In the steel sheet piles shown in FIGS. 15 to 17, since the outer surface and the inner surface of the flange portion are flat, almost no adhesion between concrete and steel sheet piles can be expected. Therefore, when calculating the strength of a concrete continuous underground wall (steel connecting wall), the concrete is ignored and the design is performed assuming the strength of the steel sheet pile.

Alternatively, as in the steel sheet pile shown in FIG. 18, a hole is formed in the flange portion and the web portion so that the concrete can wrap around the hole of the steel sheet pile and the discontinuity with the concrete can be reduced. It has been proposed to integrate the sheet pile and concrete. When using steel sheet piles, there is no need to create a rebar cage at the construction site,
There is no need to secure a wide working space for assembling the reinforcing bars.

[0007]

However, when a continuous concrete underground wall (steel connecting wall) is constructed and one of the grounds partitioned by the underground wall is excavated, the wall of the steel connecting wall is constructed. The body is subjected to bending deformation by receiving an external force such as earth pressure. Figure 2
As shown in, consider the cross section of the steel connecting wall (the section having the surface normal perpendicular to the normal direction of the wall surface of the steel connecting wall and the vertical direction). In FIG. 2, when the ground on the left side of the steel connecting wall 8 is excavated, an external force 14 such as earth pressure is applied from the right side of the steel connecting wall 8. When earth pressure is applied, bending deformation (displacement amount 13) occurs in the wall body of the steel connecting wall. At this time, if the shear stress generated on the contact surface between the concrete and the steel sheet pile is less than the adhesive strength between the concrete and the steel sheet pile, the concrete and the steel sheet pile are in an integrated (synthetic) state, and the soil External force such as pressure is supported by concrete and steel sheet pile. However, when the shearing stress generated on the contact surface between the concrete and the steel sheet pile is equal to or higher than the adhesive strength between the concrete and the steel sheet pile, the concrete and the steel sheet pile are separated from each other, and the function as the synthetic member is lost.

That is, in the steel sheet piles shown in FIGS. 15 to 17, since the outer surface and the inner surface of the flange portion are flat, the adhesion between concrete and the steel sheet pile can hardly be expected. When the adhesion between the concrete and the steel sheet pile is broken (that is, the state where the concrete and the steel sheet pile are not integrated), the external force such as earth pressure is supported only by the steel sheet pile. Therefore, when the steel sheet piles shown in FIGS. 15 to 17 are used, (1) the thickness of the steel sheet pile must be considerably increased, and (2) the integration of concrete and steel sheet piles (synthesis) The problem is that the wall thickness of the steel connecting wall becomes larger than when it is done.

Further, as shown in FIG. 18, when the steel sheet pile and the concrete are integrated by making holes in the flange portion and the web portion of the steel sheet pile so that the concrete can wrap around the holes of the steel sheet pile. However, there is a problem that the second moment of area with respect to an external force such as the strength and earth pressure of the steel sheet pile is reduced due to the cutout defect portion of the flange portion and the web portion.

Therefore, an object of the present invention is (1) a large peel resistance between steel sheet pile and concrete, and (2) a peel resistance between concrete and steel sheet pile, especially against bending deformation such as earth pressure. (3) It is to provide a steel sheet pile and a steel connecting wall capable of reducing the wall thickness of a continuous concrete underground wall.

[0011]

In the steel sheet pile according to the first aspect of the present invention, a plurality of ribs are formed on at least one surface, and the transverse cross section of the rib is such that the maximum width of the rib is larger than the width of the root of the rib. It is characterized by being

In the steel sheet pile according to the second invention of the present application, a plurality of grooves are formed on at least one surface, and the transverse cross section of the groove is such that the maximum width of the groove is larger than the aperture width of the opening of the groove. It is characterized by being present.

A third invention of the present application is a steel sheet pile having a flange and a web, wherein a plurality of ribs are formed on at least one surface of a steel plate forming the flange, and a cross section of the rib has the steel plate and the rib. It is characterized in that the maximum width of the rib is larger than the width of the root of the rib.

A fourth invention of the present application is a steel sheet pile having a flange and a web, wherein a plurality of grooves are formed on at least one surface of a steel plate forming the flange, and a cross section of the groove has an opening portion of the groove. It is characterized in that the maximum width of the groove is larger than the aperture width of.

The steel connecting wall of the fifth invention of the present application comprises the steel sheet pile of the first invention or the third invention of the present application built in a groove excavated in the ground, and concrete cast in the groove. It has a special feature.

The steel connecting wall of the sixth invention of the present application comprises the steel sheet pile of the second invention or the third invention of the present application built in a groove excavated in the ground, and concrete cast in the groove. It has a special feature. The steel sheet pile referred to in the present invention includes a square steel pipe sheet pile.

[0017]

In the steel connecting wall of the fifth invention of the present application, the maximum width of the rib is larger than the width of the base of the steel plate and the rib in the cross section of the rib formed on the surface of the steel plate. The ribs of the steel sheet pile of the first invention or the third invention enable the steel plate and the concrete to be integrated. In the steel connecting wall of the sixth invention of the present application, the maximum width of the groove is larger than the aperture width of the opening of the groove in the cross section of the groove formed on the surface of the steel sheet. 4 By the groove of the steel sheet pile of the invention,
The steel plate and concrete are integrated. The steel sheet pile referred to in the present invention includes a square steel pipe sheet pile.

Further, since the steel sheet pile of the present invention can be manufactured in a factory in advance, the product reliability is high. Furthermore, since it can be transported to the site after it is commercialized, it can be used as it is at the construction site.

In the steel connecting wall of the fifth invention of the present application using the steel sheet pile of the first invention or the third invention of the present application, the peel strength at the contact surface between the concrete and the steel plate is The rib according to claim 1 or 3, wherein a plurality of ribs are formed on at least one surface of the steel plate (hereinafter, referred to as “special rib”).
That) depends on the shear strength of the concrete sandwiched between. In the steel connecting wall of the sixth invention of the present application using the steel sheet pile of the second invention or the fourth invention of the present application, the peel strength at the contact surface between the concrete and the steel plate is formed in plural on at least one surface of the steel plate. It depends on the shear strength of the concrete sandwiched between the recesses of the groove according to claim 2 or claim 4 (hereinafter referred to as “special groove”). Therefore, the concrete and the steel plate are prevented from peeling off, and the two can be integrally deformed to strongly resist external force. Therefore, at the time of designing, the effective cross section of the continuous concrete underground wall can be considered as a composite cross section of concrete and steel plate, so that the wall thickness of the steel connecting wall can be reduced.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described based on the embodiments shown in the drawings.

[Embodiment 1] FIG. 1 is a perspective view showing an embodiment of a steel connecting wall of the fifth invention of the present application using the steel sheet pile of the third invention of the present application, and FIG. 2 is a steel connecting wall of the fifth invention of the present application. Partial perspective view of the wall, FIG.
Is a cross-sectional view showing one embodiment of the shape of the special rib of the steel sheet pile of the third invention of the present application, and FIG. 5 is a schematic view showing the state of the special rib when the steel sheet pile of the third invention of the present application is bent.

As shown in FIG. 1, a large number of steel sheet piles 1 are built into a continuous wall excavation hole to form a continuous wall, and then concrete 5 is poured to form a steel continuous wall 8 (concrete continuous underground). Wall) will be constructed. 6 is post-cast concrete, and 7 is a joint with post-cast concrete.

The steel sheet pile 1 is made of a ribbed steel plate in which a plurality of ribs (special ribs) 3 having a dovetail-shaped cross section are formed on both sides of the steel plate 2. The rib means a strip-like shape in which the protrusions are continuous, and is distinguished from a projection in which the protrusions partially protrude. In the dovetail-shaped cross section of the special rib 3, as shown in FIG. 3, in order to improve the adhesion between the steel plate and the concrete and increase the peeling resistance, the maximum width of the rib 3, that is, the steel plate 2, The outer side length 31 is larger than the width of the base of the steel plate 2 and the rib 3, that is, the inner side length 32 (31> 32).

Next, the operation of this embodiment will be described.
The dimensions of the special rib of this embodiment shown in FIG. 3 are considered as follows. h = 3.0 mm, a = h, θ = 60 °, l = 30-40 mm. However, h: rib height, a: rib width, θ: rib angle, l: rib interval, t: plate thickness.

When the steel sheet pile 1 is bent, whether or not the concrete and the steel sheet pile are separated is determined by the force A for the concrete and the steel sheet pile to separate and the force (adhesive force) for resisting the separation. Determined by the size relationship with B. That is, if A> B, peeling occurs (1) If A ≦ B, peeling does not occur (2).

FIG. 6 is a schematic view showing a state of a joint surface between a steel sheet pile having a smooth surface and concrete. FIG. 6 shows a sectional view having a wall surface normal of the steel connecting wall and a surface normal perpendicular to the vertical direction. On a joint surface between concrete and steel sheet pile, a joint between concrete and steel sheet pile having a unit width in a direction perpendicular to the vertical direction (in FIG. 6, a direction perpendicular to the paper surface) and a length l in the vertical direction. Consider the plane l _i ¹ . The adhesive force b _l ¹ between the concrete and the steel sheet pile acting on the joint surface l _i ¹ is pl (b _l ¹ = pl). Where p
Indicates the adhesive force between the concrete and the steel plate per unit area. Generally, the adhesive force p per unit area of the joint surface between the steel plate and the concrete is very small. Therefore, when an external force is applied to the joint surface between the steel plate and the concrete not having ribs on the surface, the state of formula (1) (A> B) is established and peeling occurs. Therefore, the synthetic effect of steel plate (steel sheet pile) and concrete cannot be expected.

FIG. 7 and FIG. 8 are schematic views showing a state of a joint surface between a steel sheet pile provided with ribs and concrete. 7,
FIG. 8 shows a sectional view having a wall surface normal of the steel connecting wall and a surface normal perpendicular to the vertical direction. FIG. 7 shows a case where ribs having a rectangular cross section are provided at intervals of length l in the vertical direction. FIG. 8 shows a case where the intervals between the special ribs are provided at intervals of length l in the vertical direction in the steel sheet pile according to the third invention (first invention) of the present application. Here, the distance between the ribs indicates the distance between the centers of the ribs.

As shown in FIG. 7, it has a unit width in the direction perpendicular to the vertical direction (the direction perpendicular to the paper surface in FIG. 7) in the joint surface between the concrete and the steel sheet pile, and has a unit width of 2 in the vertical direction. Consider a region of length l including a concave portion sandwiched by two ribs (joint face l _i ² between concrete and steel sheet pile).
Adhesive force b acting on joint surface l _i ² between concrete and steel sheet pile
_l ² increases by 2 μσt as shown in the equation (3). b _l ² = pl + 2μσt- (3) where, p: adhesive force per unit area of the joint surface between steel plate and concrete, μ: friction coefficient between steel and concrete, σ: compressive stress applied to concrete, l: rib Vertical interval, t: height of rib. That is, when an external force (bending moment) is applied to the steel connecting wall, compressive stress is applied to the concrete in the region sandwiched by the ribs, and compressive stress is applied to the side surfaces of the ribs. Due to this compressive stress, a frictional force is generated on the side surface of the rib. Therefore,
It is considered that the adhesive force b _l ² between the concrete and the steel sheet pile increases by the amount (2σμt) contributed by the frictional force.
Although the peeling force increases as the external force (bending moment) applied to the steel connecting wall increases, the compressive stress σ applied to the concrete increases as the external force (bending moment) increases. Therefore, it is considered that the adhesive force acting on the joint surface between the concrete and the steel sheet pile can be increased by providing the ribs on the steel sheet pile.

Further, in the present invention, the pl described above is used.
In addition to 2 μσt and 2, it is considered that the shape of the special rib contributes to the improvement of the adhesive force between the concrete and the steel sheet pile. As shown in FIG. 8, the direction perpendicular to the vertical direction in the joint surface between the concrete and the steel sheet pile (in FIG. 8, the direction perpendicular to the paper surface).
Consider a region having a unit width of 1 and a length 1 including a concave portion sandwiched by two special ribs in the vertical direction (joint surface l _i ³ between concrete and steel sheet pile). In the case of the special rib shape, in order to separate concrete and steel sheet pile,
It is considered that the concrete corresponding to the length aa '(that is, the height of the special rib) needs to be sheared and broken. At the joint surface l _i ³ , where the increase in the adhesive force caused by the shape of the special rib is r, r = 2τ _C t ─ (4) where τ _C is the allowable shear stress of the material strength of concrete, and t is the rib It is considered to be height. Therefore, in the case of a special rib, the adhesive force b acting on the joint surface l _i ³ between concrete and steel sheet pile
_l ³ is b _l ³ = pl + 2μσt + 2τ _C t ─ (5) where p: adhesive force per unit area between the joint surface of steel plate and concrete, μ: friction coefficient between steel and concrete, σ: added to concrete It is considered that compressive stress, l: vertical spacing of ribs, t: height of ribs, τ _C : allowable shear stress due to concrete material strength. Generally, the allowable shear stress τ _C of concrete is larger than the adhesive force p between the steel and the concrete per unit area and the compressive stress σ applied to the concrete.
Therefore, it is considered that the adhesive force between the concrete and the steel sheet pile is increased by providing the steel sheet pile with the special rib.

Therefore, the concrete and the steel plate are completely integrated, and peeling does not occur. Then, when resisting an external force, the synthetic effect of the concrete and the steel plate due to the integration is exerted, and the cross section can be made smaller, which is economically advantageous as described below. (1) The amount of steel plate and concrete used is small. (2) The effective use area will increase, and the reduction of wall thickness will reduce excavated soil and its treatment facility, as well as industrial waste.

[Embodiment 2] FIG. 4 is a sectional view showing one embodiment of the special groove of the steel sheet pile according to the fourth invention of the present application. As shown in FIG. 4, the steel sheet pile 1 is made of a grooved steel plate in which a plurality of grooves (special grooves) 4 having a dovetail-shaped cross section are formed on both surfaces of the steel plate 2. In the dovetail-shaped cross section of the special groove 4, the maximum width of the special groove 4, that is, the length of the bottom side of the special groove 4 is increased in order to improve the adhesion between the steel plate and the concrete and increase the peeling resistance. 41 is the aperture width of the opening of the special groove 4,
That is, it is larger than the side length 42 of the opening of the special groove 4 (41
> 42). The dimensions of the special groove of this embodiment shown in FIG.
The following are possible: h = 3.0 mm, a = h, θ = 60 °, l = 30-40 mm. However, h: groove depth, a: groove width, θ: groove angle, l: groove interval, t: plate thickness.

Also in the steel connecting wall of the sixth invention of the present application, FIG.
Due to the action of the special groove 4 of the steel sheet pile 1 shown in FIG.
When resisting an external force, the synthetic effect of the concrete and the steel plate is exerted, and the cross section can be reduced.

In the first and second embodiments, the ribs are dovetail-shaped and the grooves are dovetail-shaped, and the cross section thereof is a so-called trapezoidal shape, but each side of the trapezoidal shape is formed by a curved line. Good. Further, within the scope of claims 1 to 4,
The cross section may be circular or elliptical.

When manufacturing the steel sheet pile of the third invention of the present application,
The linear steel sheet piles having a plurality of ribs having a maximum width larger than the width of the root belonging to the first invention of the present application formed on at least one surface may be connected in a pair by a web. Similarly, when manufacturing the steel sheet pile of the fourth invention of the present application, a pair of linear steel sheet piles having a maximum width belonging to the second invention of the present application and having a plurality of grooves having a maximum width larger than the width of the opening are formed on at least one surface with a web You may connect it to.

Further, as shown in FIG. 14, after constructing the steel connecting wall, the concrete on the surface where the ground is excavated is once removed from the steel sheet pile, and then concrete is placed again to make the steel connecting wall. It is also possible to use as the inner wall of the underground building. When the steel sheet piles shown in FIGS. 15 to 18 are used, a joining device such as a stat gibber streak is arranged at the joint with the post-cast concrete such as the inner wall, floor slab, and beam to secure the required strength of the joint. There is a need. However, the work of providing a connecting device such as a stud girdle bar on the steel connecting wall requires a great deal of labor.

Further, according to the steel connecting walls of the first and second embodiments of the present invention, the special ribs or grooves function to prevent the concrete and the steel sheet pile from slipping off like the dowel, stud or shear connector. Fulfill Therefore, if a special rib or special groove is provided on the outer surface of the flange part of the steel sheet pile, when removing the concrete on the wall surface of the steel connecting wall (concrete continuous underground wall) and then post-casting concrete again, It is possible to eliminate or reduce the time and effort for joining a joining device such as a dowel, a stud or a shear connector to a steel sheet pile at a factory or a construction site. If importance is not placed on the adhesion between the post-cast concrete and the steel sheet pile, no rib or groove may be provided on the outer surface of the flange of the steel sheet pile. The ribs and grooves provided on the outer surface of the flange of the steel sheet pile may be normal ribs or grooves having a rectangular cross section.

[0037]

As described above, according to the present invention, the following industrially useful effects are brought about. Improves the adhesion between concrete and steel sheet piles compared to concrete underground walls using reinforced cages as structures, or continuous steel underground walls or steel plates with normal ribs as structures. As a result, the wall thickness can be reduced, construction costs can be reduced, and the site can be effectively used. Since no on-site construction yard is required and the wall thickness can be reduced, excavated soil and its treatment facility or industrial waste can be reduced.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of a steel connecting wall of a fifth invention of the present application.

FIG. 2 is a partial perspective view of a steel connecting wall of the fifth invention of the present application.

FIG. 3 is a cross-sectional view showing one embodiment of the shape of the special rib of the steel sheet pile according to the third invention of the present application.

FIG. 4 is a cross-sectional view showing one embodiment of the special groove of the steel sheet pile according to the fourth invention of the present application.

FIG. 5 is a schematic view showing a state of special ribs when the steel sheet pile according to the third invention of the present application is bent.

FIG. 6 is a schematic view showing a state of a joint surface between a steel sheet pile having a smooth surface and concrete.

FIG. 7 is a schematic view showing a state of a joint surface between a steel sheet pile having a rectangular cross section of a rib and concrete.

FIG. 8 is a schematic view showing a state of a joint surface between a steel sheet pile and concrete of the third invention of the present application.

FIG. 9 is a side view showing an example of a conventional reinforcing bar cage.

FIG. 10 is a front view showing an example of a conventional reinforcing bar cage.

11 is a cross-sectional view taken along the line AA of FIG.

12 is a sectional view taken along line BB of FIG.

FIG. 13 is a perspective view showing a joint state between a connecting wall using a reinforcing bar cage and post-cast concrete.

FIG. 14 is a perspective view showing a joining state of a steel continuous wall made of a normal steel plate and post-cast concrete.

FIG. 15 is a perspective view showing a conventional steel sheet pile using a normal steel sheet.

FIG. 16 is a perspective view showing a conventional steel sheet pile using a normal steel sheet.

FIG. 17 is a perspective view showing a conventional steel sheet pile using a normal steel sheet.

FIG. 18 is a perspective view showing a conventional steel sheet pile using a normal steel sheet.

[Explanation of symbols]

 1 steel sheet pile 2 steel plate 3 rib 31 outer side of rib 32 inner side of rib 4 groove 41 side of groove bottom 42 side of groove opening 5 concrete 6 post-cast concrete 7 joint with post-cast concrete 8 steel Wall made of steel 9 Reinforcing cage 10 Shade connector 11 Stud welded part 12 Stud 13 Bending by bending 14 Earth pressure and water pressure 15 Steel sheet pile made of ordinary steel plate

Claims (6)

[Claims] 1. A steel sheet pile, wherein a plurality of ribs are formed on at least one surface, and a cross section of the rib has a maximum width of the rib larger than a width of a root of the rib. 2. A steel characterized in that a plurality of grooves are formed on at least one surface, and a cross-section of the groove is such that the maximum width of the groove is larger than the aperture width of the opening of the groove. Sheet pile. 3. A steel sheet pile having a flange and a web, wherein a plurality of ribs are formed on at least one surface of a steel plate forming the flange, and a cross section of the rib has a base of the steel plate and the rib. A steel sheet pile, wherein the maximum width of the rib is larger than the width. 4. A steel sheet pile having a flange and a web, wherein a plurality of grooves are formed on at least one surface of a steel plate forming the flange, and a cross section of the groove is larger than a diameter width of an opening of the groove. Also, a steel sheet pile characterized in that the maximum width of the groove is larger. 5. A steel ream consisting of the steel sheet pile according to claim 1 or 3 built in a groove excavated in the ground, and concrete cast into the groove. wall. 6. A steel ream consisting of the steel sheet pile according to claim 2, which is built in a groove excavated in the ground, and concrete cast in the groove. wall.