JP2012017556A - Steel sheet pile underground wall structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a steel sheet pile underground wall structure in which in-plane-direction shear stiffness and strength are improved so as to be used as an earthquake-resisting wall, while reducing a construction period and a construction cost by using a steel sheet pile.SOLUTION: By attaching stiffening members 6 to a wall body 3 that is constituted by a plurality of steel sheet piles 2, shearing force acting in the in-plane direction of the wall is borne by the stiffening members 6, which improves the shear stiffness and the shear strength of the wall body 3 so as to serve as an earthquake-resisting wall. Especially, by stiffening a position forming a compression area due to the shearing force by means of the stiffening members 6, the buckling of the sheet piles 2 is able to be prevented. Therefore, the wall body 3 constituted by a plurality of steel sheet piles 2 is able to be used as the earthquake-resisting wall, which is able to reduce construction labor and cost remarkably, while reducing a construction period and a construction cost as compared with building an RC underground wall.

Description

  The present invention relates to a steel sheet pile underground wall structure, and more particularly to a steel sheet pile underground wall structure including a wall main body made of a plurality of steel sheet piles.

  Conventionally, reinforced concrete underground outer walls (RC underground walls) are often used as the underground outer walls of buildings, etc., but in order to build such RC underground walls, underground excavation is performed using temporary earth retaining. This requires a lot of work, such as placing reinforcement and formwork inside the excavated temporary earth retaining wall, and curing after placing concrete, leading to a longer construction period, and the temporary earth retaining material is discarded. There is an inconvenience that the construction cost increases due to being abandoned as a frame.

  As an example of a conventional structure, excavation is performed using a steel sheet pile as a temporary earth retaining wall, an RC wall is cast in place on the inside of the steel sheet pile, and this RC wall and the steel sheet pile are combined with the stud reinforcing bar. A steel sheet pile underground wall structure has been proposed. (For example, refer nonpatent literature 1).

“Summary Report on Building Technology Performance Proof Evaluation J-WALL Construction Method—Construction Composite Underground Wall Construction Method Using Steel Sheet Pile of Retaining Wall”, January 2008, Japan Building Research Institute

However, in the conventional steel sheet pile underground wall structure described in Non-Patent Document 1, concrete curing and stud reinforcement welding are required, so there is a concern that the construction period will be prolonged and the construction cost will increase.
In addition, when a steel sheet pile alone is used to form an underground wall structure without building an RC wall, if a shear load is applied to the building, a shear force is generated in the in-plane direction of the steel sheet pile. Has a problem that the steel sheet pile wall undergoes shear buckling to cause a large deformation and a decrease in shear rigidity or yield strength.

  The purpose of the present invention is to improve the shear rigidity and proof stress in the in-plane direction while providing a basement wall structure using steel sheet piles with stiffening members in appropriate positions, while reducing the construction period and construction costs. It is to be used as a seismic wall.

  The steel sheet pile underground wall structure of the present invention includes a wall main body made of a steel sheet pile driven into the ground, and the wall main body joins a plurality of horizontal members provided in the horizontal direction of the building to form an underground space. It is a sheet pile underground wall structure, and in the underground space, joints of a plurality of adjacent steel sheet piles among the steel sheet piles are rigidly connected over a region between the depth directions of the plurality of horizontal members. An integrated steel sheet pile wall is formed, and the wall body is formed with a concave and convex portion consisting of a concave portion and a convex portion, and a position across the diagonal line connecting the four corners of the integrated steel sheet pile wall And a plurality of stiffening members for shearing and stiffening the integrated steel sheet pile wall.

According to the present invention described above, by providing the stiffening member, the steel sheet pile can be shear stiffened against the in-plane shear force of the wall body, and the shear rigidity and shear strength of the wall body are improved. Can function as a seismic wall.
In addition, since it can function as a seismic wall without the need for RC wall construction, construction labor and costs can be greatly reduced compared to conventional RC underground walls, and construction time and construction costs can be reduced. Is possible.
Here, the stiffening member only needs to be set to a height effective for shear stiffening in the wall body, for example, the position that becomes the compression region when a shearing force acts in the in-plane direction of the wall body, Stiffening members may be provided at appropriately set positions such as a position where local buckling is expected in each steel sheet pile, a position where overall buckling as a wall body is expected, and the like.

At this time, in the steel sheet pile underground wall structure of the present invention, a plurality of stiffening members that shear and stiffen the integrated steel sheet pile wall are arranged, and the integrated steel sheet pile wall is a column. A plurality of such members are arranged at positions crossing diagonal lines connecting four corners of a quadrangle having four sides that are joined to a vertical member such as a beam and a horizontal member such as a floor.
According to such a configuration, the compression region (compression brace) and the tensile region when the underground wall structure in which the steel sheet pile wall formed in the framework formed by the vertical member and the horizontal member is formed bears the shearing force. (Tensile braces) are formed at positions where the integrated steel sheet pile wall crosses the diagonal line connecting the four corners of the quadrangle with the sides joining the vertical members such as columns and horizontal members such as beams and floors. In addition, since a plurality of stiffening members are disposed at positions across the diagonal line, the shear rigidity and shear strength of the wall body can be improved.

Furthermore, in the steel sheet pile underground wall structure of the present invention, the steel sheet pile wall extends in the extending direction of the wall body, and extends in the direction of extension of the wall body continuously to both end portions of the flange. A pair of webs extending in a plane, and the stiffening member is closed by the stiffening member, the flange, and the pair of webs at the position of the convex portion. As described above, it is preferable that both side edges of the stiffening member are fixed by welding.
According to such a configuration, both side edges of the stiffening member are fixed by welding joint so that the concave portion is closed by the stiffening member, the flange, and the pair of webs at the position of the convex portion. By providing this stiffening member in the extending direction of the wall body, the stiffening member can bear the shearing force, and the shear rigidity and proof stress of the wall body can be improved. Furthermore, the stiffening member can be prevented from projecting to the front side of the steel sheet pile, that is, the underground space, and the underground space can be effectively used.

Further, in the steel sheet pile underground wall structure of the present invention, the steel sheet pile wall extends in the extending direction of the wall main body, and extends to the extending direction of the wall main body continuously from both end portions of the flange. A pair of webs extending in the plane, and the stiffening member is at the position corresponding to the concave portion, and at least two of the three end edges of the stiffening member are the pair of webs. The three stiffening members may be fixed to the flange and the pair of webs by welding joints.
In this case, the stiffening member may be formed in parallel with a horizontal member such as a beam or a floor, and its three edges may be fixed to the flange and the pair of webs by welding.
According to such a configuration, the stiffening member functioning as a stiffener can be obtained by welding the stiffening member parallel to the horizontal direction intersecting the longitudinal direction (vertical direction) of the steel sheet pile to the flange and the web. The buckling of the flange and the web can be prevented, and the shear strength as the wall body can be improved. Furthermore, the stiffening member can be prevented from projecting to the front side of the steel sheet pile, that is, the underground space, and the underground space can be effectively used.
The stiffening member is parallel to the horizontal direction, but may be fixed by welding at an arbitrary angle with respect to the horizontal direction.

Further, in the steel sheet pile underground wall structure of the present invention, the steel sheet pile wall extends in the extending direction of the wall main body, and extends to the extending direction of the wall main body continuously from both end portions of the flange. A pair of webs extending in-plane and a second flange extending in parallel with the flanges, and a part of the stiffening member is formed at both side edges thereof Are preferably fixed to the second flanges of the adjacent steel sheet piles by welding.
According to such a configuration, since the number of the stiffening members arranged is increased by welding the stiffening members across the second flanges in the adjacent steel sheet piles, a greater shear force is borne. Can be made.

  According to the steel sheet pile underground wall structure of the present invention as described above, by installing an appropriate number of stiffening members at appropriate positions on the underground space side of the wall body constituted by a plurality of steel sheet piles, It is possible to increase the shear strength and shear strength of the wall body by applying a shear force to itself or preventing the buckling of the steel sheet pile stiffened by a stiffening member and increasing the shear strength of the steel sheet pile. it can. Therefore, the shear rigidity and proof stress in the in-plane direction of the steel sheet pile underground wall can be improved and used as the earthquake resistant wall. By constructing the underground earthquake resistant wall using such a steel sheet pile, the conventional RC underground wall can be used. The construction period and construction cost can be significantly reduced.

It is a perspective view which shows the steel sheet pile underground wall which concerns on 1st Embodiment of this invention. It is a front view which shows the said steel sheet pile underground wall. It is a cross-sectional view showing the steel sheet pile underground wall. It is the cross-sectional view and front view which show the steel sheet pile in the said steel sheet pile underground wall. It is a front view which shows the effect | action of the said steel sheet pile underground wall. It is a front view which shows the modification of the said steel sheet pile underground wall. It is the cross-sectional view and front view which show the modification of the said steel sheet pile. It is the cross-sectional view and front view which show the steel sheet pile underground wall of 2nd Embodiment.

Hereinafter, each embodiment of the present invention will be described with reference to the drawings.
In the second and subsequent embodiments, the same constituent members as those described in the first embodiment and the constituent members having the same functions are denoted by the same reference numerals as those in the first embodiment. Those descriptions are omitted or simplified.

[First Embodiment]
1 and 2, a steel sheet pile underground wall 1 is a continuous underground wall that divides a basement space S, which is a space on the front side, and a back side ground G, on the back side. A wall body 3 composed of a steel sheet pile 2 is provided. The basement space S is surrounded by the wall body 3 and is divided into upper and lower sections by the basement floor slab 4 and the first floor slab 5. Furthermore, the wall body 3 is connected to the pillar A located on the basement space S side.

  The steel sheet pile 2 is manufactured by hot rolling. As shown in FIGS. 3 and 4, the steel sheet pile 2 is positioned at the center of the cross section and extends in the extending direction of the wall body 3, and both sides of the first flange 21. A pair of webs 22 extending to the basement space S side in a plane that is continuous with the edge and perpendicular to the extending direction of the wall body, and extends in parallel with the first flange 21 from the leading edges of the pair of webs 22. It is a hat-shaped steel sheet pile having a pair of second flanges 23 and a pair of joint portions 24 provided at the leading edges of the pair of second flanges 23. Each of these steel sheet piles 2 is provided with the first flange 21 provided on the ground G side, the second flange 23 provided on the basement space S side, and fitting the joint portions 24 positioned on the basement space S side. By combining, adjacent steel sheet piles 2 are connected to each other, whereby the wall body 3 is continuously formed.

  Three steel sheet piles 2 adjacent to each other among the plurality of steel sheet piles 2 are connected by a welded portion 25 in which the joint portions 24 are welded together in the height range of the basement space S. And in the connected three steel sheet piles 2, a pair of steel sheet piles 2 are respectively provided at two upper and lower positions of the two left and right steel sheet piles 2A and one middle position in the height direction of one central sheet pile 2B. As shown in FIG. 2, these stiffening members 6 are provided with three steel sheet piles 2 connected between adjacent columns A as shown in FIG. When viewed from the space S side, they are arranged on a diagonal line. Such a stiffening member 6 is for shearing and stiffening the steel sheet pile 2, and a part of the shearing force acting on the wall body 3 can be borne by the stiffening member 6. 2 also functions as a buckling prevention material for preventing buckling.

  The stiffening member 6 is composed of a steel plate along the extending direction of the wall body 3 and is fixed to the steel sheet pile 2 by a welded portion 61 having both side edges welded to the web 22. Moreover, the stiffening member 6 is provided in the wall surface orthogonal direction (up-down direction of FIG. 3) of the wall main body 3, as shown in FIG. Moreover, as shown in FIG. 4, the stiffening member 6 may be previously fixed to the steel sheet pile 2 on the ground by welding and may be driven into the ground G together with the steel sheet pile 2 in the fixed state. Since it is assumed that the construction will be affected due to the blockage phenomenon, the steel sheet pile 2 is driven into the ground G, and then the ground on the basement space S side is excavated and then exposed to the front side of the wall body 3 exposed by field welding. It is preferably fixed.

Next, the transmission mechanism of the in-wall shear force when a horizontal force acts on the steel sheet pile underground wall 1 will be described with reference to FIG. Here, as described above, the three steel sheet piles 2 connected to each other by welding will be described.
In FIG. 5, when the horizontal force P acts on the first floor slab 5 position from the left to the right in the figure, the reaction force P ′ acts on the basement floor slab 4 position supported by the ground G, A shearing force Q is generated in the wall surface of the wall body 3. This shearing force Q is decomposed into a compressive force in a compression region (compression brace) C indicated by a right-downward hatch in FIG. 5 and a tensile force in a tensile region (tensile brace) T indicated by a right-upward hatch. The compression region C and the tensile region T are formed diagonally with respect to the horizontal direction (vertical direction) in the wall surface of the wall body 3, and the compressive stress level and the tensile stress level corresponding to the widths of the respective regions C and T are formed. Has come to occur. Moreover, in the welding part 25 which connects the steel sheet piles 2 to each other, a vertical shearing force R that causes the adjacent steel sheet piles 2 to be shifted up and down is generated, and the welding part 25 has a shearing force R exceeding the shearing force R. The welding strength is set.

In the wall body 3 in which the compression region C and the tension region T as described above are formed, the stiffening member 6 is provided at a position where these regions C and T are formed. In particular, since the first flange 21 of the steel sheet pile 2 that becomes the compression region C is easily buckled out of plane, the stiffening member 6 corresponds to the position where the compression region C is formed, as shown in FIG. The two steel sheet piles 2A on the left and right are provided at two locations on the upper and lower sides, and the middle in the height direction of one steel sheet pile 2B on the center. Therefore, buckling of the steel sheet pile 2 in the compression region C can be prevented, and the stiffening member 6 bears a part of the compression force generated in the compression region C and the tensile force generated in the tension region T. The shear strength of 3 can be improved. Furthermore, deformation such as torsion of the steel sheet pile 2 when a shearing force is applied can be suppressed by the stiffening member 6, and the shear rigidity of the wall body 3 can be improved.
The stiffening member may be fixed by welding at an arbitrary angle with respect to the horizontal direction, but is preferably parallel to the horizontal direction. This is because the shearing force acting on the integrated steel sheet pile wall acts in the horizontal direction, and therefore, when the stiffening member is mounted horizontally, the resistance area to the shearing force is maximized, which is effective.

In the present embodiment, the connection between the steel sheet piles 2 and the installation location of the stiffening member 6 are not limited to those described above, and the structure shown in FIG.
In FIG. 6, two adjacent steel sheet piles 2 among the plurality of steel sheet piles 2 are connected by a welded portion 25 in the height range of the basement space S. A stiffening member 6 is attached to each of the two connected steel sheet piles 2.
Further, the stiffening member 6 is not limited to a steel plate extending in the direction parallel to the wall surface of the wall body 3, and the structure shown in FIG.
In FIG. 7, a plurality of stiffening members 6 </ b> A are provided at a predetermined interval in the vertical direction so as to straddle the diagonal line, are orthogonal to the wall surface of the wall body 3, parallel to the horizontal direction, and orthogonal to the longitudinal direction of the steel sheet pile 2. The steel sheet pile is composed of a welded portion 62 in which both left and right edges are welded to the web 22, and a welded portion 63 in which the side edge in the direction orthogonal to the wall surface is welded to the first flange 21. 2 is fixed. Such a stiffening member 6A is fixed to the steel sheet pile 2 by field welding on the front side of the wall body 3 exposed after the steel sheet pile 2 is driven into the ground G and the ground on the basement space S side is excavated.

According to the steel sheet pile underground wall 1 of this embodiment as described above, the following effects are obtained.
That is, by attaching the stiffening members 6 and 6A to the positions that become the compression region C and the tension region T with respect to the in-plane shear force Q of the wall main body 3, a part of the compression force and the tensile force is supplied to the stiffening member 6, 6A can be borne, and the shear rigidity and shear strength of the wall body 3 can be improved to function as a seismic wall. In particular, in the compression region C, shear buckling of the first flange 21 of the steel sheet pile 2 can be prevented by shearing and stiffening the steel sheet pile 2 with the stiffening members 6 and 6A. Therefore, since the wall main body 3 composed of a plurality of steel sheet piles 2 can be used as a seismic wall, it is possible to greatly reduce the labor and cost of construction compared to the case of constructing a conventional RC underground wall. The construction period can be shortened and the construction cost can be reduced.

[Second Embodiment]
Next, the steel sheet pile underground wall 1A of 2nd Embodiment of this invention is demonstrated based on FIG.
In FIG. 8, the steel sheet pile underground wall 1 </ b> A is substantially the same as the first embodiment, although the attachment position of the stiffening member 6 is different from that of the first embodiment. Hereinafter, the differences will be described in detail.
In the wall main body 3 of the steel sheet pile basement wall 1 </ b> A, among the plurality of steel sheet piles 2, the three steel sheet piles 2 adjacent to each other between the columns A are connected by the welded portion 25, and the steel adjacent to each other through the welded portion 25. A stiffening member 6B is attached to the front surface side across the joint portion 24 of the sheet pile 2. The stiffening member 6B is made of a steel plate along the direction parallel to the wall surface of the wall main body 3, and the steel sheet pile 2 is welded to the second flange 23 of the adjacent steel sheet pile 2 by welding the both side edges thereof. It is fixed. These stiffening members 6B should just be arrange | positioned at two places up and down of the steel sheet pile 2 in the basement space S, as shown in FIG.

In addition, this invention is not limited to the said embodiment, Including other structures etc. which can achieve the objective of this invention, the deformation | transformation etc. which are shown below are also contained in this invention.
For example, in the embodiment, the underground space partitioned from the ground by the steel sheet pile basement walls 1 and 1A is the basement space S, but the basement space is not limited to the basement, and may be any appropriate space. Applicable to car parks, bicycle parking lots, tunnels such as subways and roads, and underground grooves such as drainage routes and piping routes.

Moreover, in the said embodiment, although the hat-shaped steel sheet pile was illustrated as the steel sheet pile 2, as a steel sheet pile which comprises the wall main body 3, it is not restricted to a hat-shaped steel sheet pile (steel sheet pile 2), U-shaped steel sheet pile, Z What has an appropriate cross section, such as a shaped steel sheet pile, can be used.
Furthermore, in the said embodiment, although the joint part 24 of the steel sheet pile 2 was located and provided in the underground space side (front side), not only this but the joint part which connects steel sheet piles is the ground side (back surface). Side) or at an intermediate position in the wall thickness direction of the underground wall.

Moreover, in the said embodiment, although the rectangular stiffening members 6, 6A, 6B were attached to the upper end part and lower end part of the steel sheet pile 2 in the height range of underground space, or the intermediate part of the steel sheet pile 2, Is not limited to a rectangular shape, and may be a long shape along the longitudinal direction of the steel sheet pile 2, in which case the stiffening member is a steel sheet pile over the entire length of the underground space. It may be attached to.
Further, the welded portion may be welded directly to each other, or may be welded via a steel material such as an angle or a channel, as long as it transmits a force acting between steel sheet piles.
Further, the length and plate thickness of the stiffening member 6 and the leg length in the case where the stiffening member 6 is attached to the steel sheet pile by welding joining may be designed so as to sufficiently resist the assumed shearing force.
Furthermore, the material of the stiffening member 6 should just be the same intensity | strength as a base material, or should have the material intensity | strength required by design.
Further, the stiffening member is not limited to the member fixed to the steel sheet pile by welding, and may be fixed to the steel sheet pile by an appropriate fixing means such as a bolt or a rivet.
Further, the means for connecting the steel sheet piles is not limited to welding joining, and appropriate joining means such as bolt joining and rivet joining can be used.

In addition, the best configuration, method and the like for carrying out the present invention have been disclosed in the above description, but the present invention is not limited to this. That is, the invention has been illustrated and described with particular reference to certain specific embodiments, but without departing from the spirit and scope of the invention, Various modifications can be made by those skilled in the art in terms of material, quantity, and other detailed configurations.
Therefore, the description limiting the shape, material, etc. disclosed above is an example for easy understanding of the present invention, and does not limit the present invention. The description by the name of the member which remove | excluded the limitation of one part or all of such restrictions is included in this invention.

  DESCRIPTION OF SYMBOLS 1,1A ... Steel sheet pile underground wall, 2, 2A, 2B ... Steel sheet pile, 3 ... Wall main body, 4 ... Basement floor slab (horizontal member), 5 ... First floor slab (horizontal member), 6, 6A, 6B ... Stiffening member, 21 ... first flange, 22 ... web, 23 ... second flange, 24 ... joint part, A ... column (vertical member), G ... ground, S ... basement space.

Claims (4)

A steel sheet pile underground wall structure comprising a wall main body made of a steel sheet pile driven into the ground, the wall main body joining a plurality of horizontal members provided in the horizontal direction of the building to form an underground space,
In the underground space, joints of a plurality of adjacent steel sheet piles among the steel sheet piles are rigidly connected over a region between the depth directions of the plurality of horizontal members to form an integrated steel sheet pile wall. And the wall body has a concave and convex portion composed of a concave portion and a convex portion,
A steel sheet pile underground wall structure in which a plurality of stiffening members for shearing and stiffening the integrated steel sheet pile wall are arranged at positions crossing diagonal lines connecting the four corners of the integrated steel sheet pile wall. In the steel sheet pile underground wall structure according to claim 1,
The steel sheet pile wall includes at least a flange extending in an extending direction of the wall main body and a pair of webs extending in a plane perpendicular to the extending direction of the wall main body, which are continuous from both end portions of the flange. Formed with
In the stiffening member, both side edges of the stiffening member are fixed by welding joint so that the concave portion is closed by the stiffening member, the flange and the pair of webs at the position of the convex portion. Steel sheet pile underground wall structure characterized by In the steel sheet pile underground wall structure according to claim 1,
The steel sheet pile wall includes at least a flange extending in an extending direction of the wall main body and a pair of webs extending in a plane perpendicular to the extending direction of the wall main body, which are continuous from both end portions of the flange. Formed with
The stiffening member is fixed to the pair of webs by welding joining at least two of the three end edges of the stiffening member at a position corresponding to the concave portion, or the three directions of the stiffening member The steel sheet pile underground wall structure, wherein the end edges of the steel sheet pile are fixed to the flange and the pair of webs by welding. In the steel sheet pile underground wall structure according to any one of claims 1 to 3,
The steel sheet pile wall includes a flange extending in the extending direction of the wall main body, a pair of webs extending in a plane perpendicular to the extending direction of the wall main body, continuous from both end portions of the flange, and A second flange extending in parallel with the flange continuously with the web of
A steel sheet pile underground wall structure, wherein a part of the stiffening member is fixed to the second flanges of the adjacent steel sheet piles by welding joints.

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