JP5158249B2 - Steel sheet pile and steel sheet pile foundation structure - Google Patents

Steel sheet pile and steel sheet pile foundation structure Download PDF

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JP5158249B2
JP5158249B2 JP2011266815A JP2011266815A JP5158249B2 JP 5158249 B2 JP5158249 B2 JP 5158249B2 JP 2011266815 A JP2011266815 A JP 2011266815A JP 2011266815 A JP2011266815 A JP 2011266815A JP 5158249 B2 JP5158249 B2 JP 5158249B2
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steel sheet
sheet pile
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steel material
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JP2012047041A (en
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健二 西海
真治 妙中
裕章 中山
典佳 原田
操 楠本
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Nippon Steel Corp
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本発明は、鋼矢板および鋼矢板基礎構造に関し、構造物を支持する基礎構造に利用可能で、かつ高い鉛直支持力を確実に発揮できる鋼矢板および鋼矢板基礎構造に関するものである。   TECHNICAL FIELD The present invention relates to a steel sheet pile and a steel sheet pile foundation structure, and relates to a steel sheet pile and a steel sheet pile foundation structure that can be used for a foundation structure that supports a structure and that can reliably exhibit a high vertical support force.

熱間圧延で製造される鋼矢板は、ウェブ部の両端に一対のフランジ部が配置され 前記フランジ部の先端側に継手部が配置されており、一般にU形鋼矢板やハット形鋼矢板と呼ばれている。前記鋼矢板は、複数枚を連続して地盤に打設され、河川護岸,擁壁および土留めなどの壁構造として構築され、壁構造背面から作用する土圧に対して、根入れ部の水平地盤抵抗で抵抗する構造に用いられる。
このような鋼矢板を複数連結して平面多角形状に形成された鋼矢板構造体と、コンクリート製の直接基礎とを結合した鋼矢板併用直接基礎が提案されている(例えば、特許文献1参照)。特許文献1に記載された技術は、直接基礎が比較的強固な地盤に用いられるのに対し、鋼矢板構造体を併用することにより、鋼矢板構造体で鉛直荷重を負担することで支持力の向上を図ることに加え、直接基礎を現場で建設するための型枠としても鋼矢板が利用可能なことに着目したものである。
A steel sheet pile manufactured by hot rolling has a pair of flange portions disposed at both ends of the web portion, and a joint portion disposed at the distal end side of the flange portion, generally called a U-shaped steel sheet pile or a hat-shaped steel sheet pile. It is. The steel sheet pile is continuously placed on the ground, and is constructed as a wall structure such as a river revetment, retaining wall, and earth retaining. Used for structures that resist ground resistance.
A steel sheet pile combined direct foundation in which a steel sheet pile structure formed in a planar polygonal shape by connecting a plurality of such steel sheet piles and a direct foundation made of concrete is proposed (for example, see Patent Document 1). . The technique described in Patent Document 1 is used for the ground where the foundation is relatively strong, but by using the steel sheet pile structure together, the bearing capacity of the steel sheet pile structure is borne by bearing a vertical load. In addition to the improvement, the steel sheet pile can be used as a formwork for constructing the foundation directly on site.

また、2枚のU形鋼矢板を筒状に重ね合せて溶接した、組合せ鋼矢板がある。組合せ鋼矢板は、1枚の鋼矢板と比較して断面性能を向上することができる。しかし、このような組合せ鋼矢板は、専ら曲げ性能の向上に期待した護岸や擁壁構造に用いられている。
一方、鋼矢板を比較的固い地盤に打設する場合には、鋼矢板の先端が変形する可能性があり、また長尺の鋼矢板を複数枚地盤に打設する場合には、鋼矢板の幅が拡縮して鋼矢板が打設方向に対して傾斜する可能性がある。このような鋼矢板の施工時の変形を抑制する技術として、鋼矢板の打込み端部に補強板を配置して鋼矢板先端部の変形を防止するものや(例えば、特許文献2参照)、鋼矢板の軸方向に側板部の角度を保持する補強部材を配置して鋼矢板の拡縮を防止するもの(例えば、特許文献3参照)などが提案されている。
There is also a combined steel sheet pile in which two U-shaped steel sheet piles are overlapped and welded in a cylindrical shape. The combined steel sheet pile can improve cross-sectional performance as compared with a single steel sheet pile. However, such combination steel sheet piles are used exclusively for revetments and retaining wall structures that are expected to improve bending performance.
On the other hand, when placing steel sheet piles on relatively hard ground, the tip of the steel sheet piles may be deformed, and when placing multiple steel sheet piles on the ground, There is a possibility that the width of the steel sheet pile will be increased or decreased and the steel sheet pile will be inclined with respect to the placing direction. As a technique for suppressing deformation at the time of construction of such a steel sheet pile, a reinforcing plate is disposed at the driving end of the steel sheet pile to prevent the deformation of the steel sheet pile tip (for example, see Patent Document 2), steel There has been proposed a member that arranges a reinforcing member that maintains the angle of the side plate portion in the axial direction of the sheet pile to prevent the steel sheet pile from expanding or contracting (for example, see Patent Document 3).

特開2003−138577号公報JP 2003-138777 A 実開昭62−138737号公報Japanese Utility Model Publication No. 62-138737 特開2001−32264号公報JP 2001-322264 A

特許文献1記載の鋼矢板併用直接基礎は、鋼矢板の鉛直支持力に期待した構造であるが、ここで用いられる鋼矢板は、フランジ部の継手側が開放された開断面形状であるために、支持層に根入れしても地盤の締め固め効果が極めて低く、先端の閉塞が成立しないことから、鋼矢板の先端支持力は鋼管杭などと比較して極めて小さな支持力しか発揮できない。この際、支持層への根入れ長を長くすることにより先端支持力が増加することも考えられるが、先端部での閉塞が不確実であるために確実な支持力が発現できず、支持構造としては問題である。
また、組合せ鋼矢板では、鋼矢板全長にわたり2枚の鋼矢板を溶接加工する必要があるため、加工費が過大となり、コストが高くなるという問題がある。
また,特許文献2記載の鋼矢板は、その先端補強のために比較的幅の狭い鋼板を用いて鋼矢板側端部を連結した形状である。すなわち、特許文献2には、鋼矢板の断面高さが135mmに対して、補強板の幅が150mmの例が記載されている。しかしながら、先端部を比較的幅の狭い補強板で連結した鋼矢板を固い地盤に打設した場合には、地盤抵抗が著しく増大するために、鋼矢板の折れ曲がりや補強板のめくれ上がりが生じることが、本件出願人の研究により判明した。さらには、特許文献2記載の鋼矢板では、その打設後の鉛直精度が阻害されることも判明した。従って、特許文献2記載の鋼矢板を支持構造として用いることは困難である。
The steel sheet pile combined direct foundation described in Patent Document 1 is a structure expected for the vertical support force of the steel sheet pile, but the steel sheet pile used here has an open cross-sectional shape in which the joint side of the flange portion is opened. Even if rooted in the support layer, the effect of compacting the ground is extremely low and the tip end is not closed. Therefore, the tip support force of the steel sheet pile can exhibit only a very small support force compared to a steel pipe pile or the like. At this time, it is conceivable that the tip support force increases by increasing the penetration depth into the support layer, but since the blockage at the tip part is uncertain, a reliable support force cannot be expressed, and the support structure As a problem.
Moreover, in the combined steel sheet pile, since it is necessary to weld two steel sheet piles over the entire length of the steel sheet pile, there is a problem that the processing cost becomes excessive and the cost becomes high.
Moreover, the steel sheet pile described in Patent Document 2 has a shape in which steel sheet pile side ends are connected using a relatively narrow steel plate for reinforcing the tip. That is, Patent Document 2 describes an example in which the cross-sectional height of the steel sheet pile is 135 mm and the width of the reinforcing plate is 150 mm. However, when a steel sheet pile connected at its tip with a relatively narrow reinforcing plate is placed on a hard ground, the ground resistance will increase significantly, resulting in bending of the steel sheet pile and turning up of the reinforcing plate. However, it became clear by the applicant's research. Furthermore, it was also found that the steel sheet pile described in Patent Document 2 hinders the vertical accuracy after the placement. Therefore, it is difficult to use the steel sheet pile described in Patent Document 2 as a support structure.

本発明の目的は、打設時の変形や損傷を抑制し、かつ高い鉛直支持力を確実に発揮させることができ、安価な基礎構造を構築することが可能となる鋼矢板および鋼矢板基礎構造を提供することにある。   An object of the present invention is to provide a steel sheet pile and a steel sheet pile foundation structure capable of suppressing deformation and damage at the time of placing and capable of reliably exhibiting a high vertical support force and constructing an inexpensive foundation structure. Is to provide.

本発明の鋼矢板は、ウェブ部と、このウェブ部の両端に連続して形成された一対のフランジ部と、これら一対のフランジ部の先端側に形成された継手部とを有した鋼矢板本体と、前記鋼矢板本体の長手方向先端部における前記一対のフランジ部の先端間に渡って接合され、当該鋼矢板本体の開断面を閉じる閉合鋼材とを備え、前記閉合鋼材の前記鋼矢板本体の長手方向に沿った長さ寸法が、前記ウェブ部からフランジ部先端までの当該鋼矢板本体の断面高さ寸法に対して2倍以上に設定され、前記閉合鋼材の前記長手方向先端と反対側の上端部に形成され、当該閉合鋼材から鋼矢板本体に向かって傾斜した傾斜面が形成されていることを特徴とする。   The steel sheet pile of the present invention includes a steel sheet pile main body having a web portion, a pair of flange portions formed continuously at both ends of the web portion, and a joint portion formed on the tip side of the pair of flange portions. And a closed steel material that is joined across the front ends of the pair of flange portions at the front end in the longitudinal direction of the steel sheet pile main body, and closes an open cross section of the steel sheet pile main body, and the steel sheet pile main body of the closed steel material The length dimension along the longitudinal direction is set to more than twice the cross-sectional height dimension of the steel sheet pile main body from the web part to the flange part tip, and the opposite side to the longitudinal tip of the closed steel material An inclined surface formed on the upper end portion and inclined from the closed steel material toward the steel sheet pile main body is formed.

以上の本発明によれば、鋼矢板本体の開断面を閉じる閉合鋼材の長さ寸法が鋼矢板本体の断面高さ寸法に対して2倍以上に設定されていることで、支持層などの硬質な地盤に鋼矢板の先端部を打ち込む場合でも、閉合鋼材のめくれ上がりが防止できるとともに、鋼矢板本体の変形を防止して打設後の鉛直精度も確保できる。そして、鋼矢板本体と閉合鋼材とによって先端部が閉断面形状となった鋼矢板を地盤に打設することで、閉断面部分に入り込んだ土塊が締め固められて鋼矢板の先端部が閉塞されることによって、その閉塞部分の断面積(投影面積)に応じた高い先端支持力を得ることができる。従って、支持層としての硬質な地盤に確実に打設して高い先端支持力が得られることから、支持構造として利用する場合に確実な鉛直支持力を発揮させることができ、本発明の鋼矢板を用いた安価な基礎構造を構築することができる。
また、閉合鋼材の上端部に傾斜面が形成されていることで、曲げ変形に抵抗する補強リブとして作用するために、鋼矢板本体や閉合鋼材の折れ曲がりを抑制することができる。
According to the present invention described above, the length dimension of the closed steel material that closes the open section of the steel sheet pile main body is set to be twice or more the cross sectional height dimension of the steel sheet pile main body, so Even when the tip of the steel sheet pile is driven into a soft ground, the closed steel material can be prevented from turning up, and the steel sheet pile main body can be prevented from being deformed to ensure vertical accuracy after placement. And by placing a steel sheet pile with a closed cross-sectional shape on the ground by the steel sheet pile main body and the closed steel material, the earth lump entering the closed cross-section portion is compacted and the front end portion of the steel sheet pile is closed. As a result, a high tip support force according to the cross-sectional area (projected area) of the closed portion can be obtained. Accordingly, since a high tip support force can be obtained by reliably placing on the hard ground as the support layer, a reliable vertical support force can be exhibited when used as a support structure, and the steel sheet pile of the present invention An inexpensive foundation structure using can be constructed.
Moreover, since the inclined surface is formed in the upper end part of closed steel materials, since it acts as a reinforcement rib which resists bending deformation, the bending of a steel sheet pile main body or a closed steel material can be suppressed.

この際、本発明の鋼矢板では、前記閉合鋼材の長さ寸法が前記鋼矢板本体の断面高さ寸法に対して7倍以下に設定されていることが好ましい。
このような構成によれば、閉合鋼材の長さ寸法を鋼矢板本体の断面高さ寸法に対して2倍以上かつ7倍以下に設定したことで、前述のように地盤への打設時のめくれ上がりを防止しつつ、打設時の摩擦抵抗を抑制して施工性を向上させることができる。さらに、全長に渡って2枚の鋼矢板を溶接接合した組合せ鋼矢板のように加工費が過大となることがなく、材料コストや製造コストを抑制することができる。また、本件出願人の研究により、閉合鋼材の長さ寸法を鋼矢板本体の断面高さ寸法の7倍程度に設定した場合に、鋼矢板先端部における地盤の閉塞効果が一定値に漸近することが判明したため、閉合鋼材の長さ寸法を鋼矢板本体の断面高さ寸法の7倍以下に設定することで、施工性および低コスト化とバランスさせて閉塞効果を効率よく発揮させることができる。
Under the present circumstances, in the steel sheet pile of this invention, it is preferable that the length dimension of the said closed steel material is set to 7 times or less with respect to the cross-sectional height dimension of the said steel sheet pile main body.
According to such a configuration, the length dimension of the closed steel material is set to be not less than 2 times and not more than 7 times the cross-sectional height dimension of the steel sheet pile main body. While preventing turning up, it is possible to improve the workability by suppressing the frictional resistance at the time of placing. Furthermore, the processing cost does not become excessive as in the combined steel sheet pile in which two steel sheet piles are welded over the entire length, and the material cost and the manufacturing cost can be suppressed. In addition, according to the applicant's research, when the length dimension of the closed steel material is set to about 7 times the cross-sectional height dimension of the steel sheet pile main body, the clogging effect of the ground at the steel sheet pile front end asymptotically approaches a certain value. Therefore, by setting the length dimension of the closed steel material to 7 times or less of the cross-sectional height dimension of the steel sheet pile main body, the blocking effect can be efficiently exhibited in balance with workability and cost reduction.

また、本発明の鋼矢板では、前記閉合鋼材が前記鋼矢板本体のウェブ部およびフランジ部と面対称な略コ字形断面を有して形成されていることが好ましい。
ここで、閉合鋼材としては、鋼板を溶接により加工して製作してもよいが、鋼矢板本体と同一断面を有した部材から継手部を切断したものを用い、この部材を鋼矢板本体と面対称に接合することが好ましい。
このような構成によれば、閉合鋼材が鋼矢板本体と面対称な略コ字形断面を有していることで、閉合鋼材と鋼矢板本体とで形成される閉断面部分の断面積を拡大することができ、この断面積に応じて得られる先端支持力を増大させることができる。
Moreover, in the steel sheet pile of this invention, it is preferable that the said closed steel material has the substantially U-shaped cross section which is plane-symmetrical with the web part and flange part of the said steel sheet pile main body.
Here, the closed steel material may be manufactured by welding a steel plate, but a member obtained by cutting the joint from a member having the same cross section as the steel sheet pile main body is used, and this member is connected to the steel sheet pile main body and the surface. It is preferable to join symmetrically.
According to such a configuration, the cross-sectional area of the closed cross-section portion formed by the closed steel material and the steel sheet pile main body is enlarged because the closed steel material has a substantially U-shaped cross section symmetrical to the steel sheet pile main body. The tip supporting force obtained according to this cross-sectional area can be increased.

さらに、本発明の鋼矢板では、前記閉合鋼材における前記鋼矢板本体に面した側の表面に突起が形成されていることが好ましい。
このような構成によれば、鋼矢板本体に面した側の表面つまり閉合鋼材の内側表面に突起を形成したことで、鋼矢板本体と閉合鋼材とで形成された閉断面部分に入り込んだ土塊と閉合鋼材との摩擦抵抗を大きくすることができ、鋼矢板先端部の閉塞効果を高めることができる。
Furthermore, in the steel sheet pile of this invention, it is preferable that the protrusion is formed in the surface of the side facing the said steel sheet pile main body in the said closed steel material.
According to such a configuration, by forming protrusions on the surface facing the steel sheet pile main body, that is, the inner surface of the closed steel material, the lump entering the closed cross-section portion formed by the steel sheet pile main body and the closed steel material and The frictional resistance with the closed steel material can be increased, and the blocking effect of the steel sheet pile tip can be enhanced.

また、本発明の鋼矢板では、前記鋼矢板本体および前記閉合鋼材の少なくとも一方における長手方向先端には、当該閉合鋼材から鋼矢板本体に向かって先端方向に傾斜した傾斜面が形成されていることが好ましい。
このような構成によれば、鋼矢板本体や閉合鋼材の先端部に傾斜面を形成したことで、鋼矢板を地盤(特に支持層などの硬質な地盤)に打ち込む際に、閉合鋼材に作用する地盤抵抗によるモーメントと、傾斜面に作用する地盤抵抗によるモーメントとが逆向きになり、これらのモーメントが互いに打ち消し合うことで鋼矢板本体に生じる曲げ応力を低減させることができるために、鋼矢板本体および閉合鋼材の変形をより効果的に防止することができ、鋼矢板を精度よく施工することができる。
Moreover, in the steel sheet pile of this invention, the inclined surface inclined in the front end direction toward the steel sheet pile main body from the said closed steel material is formed in the longitudinal direction front-end | tip in at least one of the said steel sheet pile main body and the said closed steel material. Is preferred.
According to such a configuration, when the steel sheet pile is driven into the ground (particularly a hard ground such as a support layer) by forming the inclined surface at the tip of the steel sheet pile main body or the closed steel material, it acts on the closed steel material. The moment caused by the ground resistance and the moment caused by the ground resistance acting on the inclined surface are reversed, and these moments cancel each other, so that the bending stress generated in the steel sheet pile body can be reduced. And the deformation of the closed steel material can be prevented more effectively, and the steel sheet pile can be constructed with high accuracy.

さらに、本発明の鋼矢板では、前記鋼矢板本体の先端が前記閉合鋼材の先端よりも先端方向に突出して形成されていることが好ましい。
このような構成によれば、鋼矢板本体の先端を閉合鋼材よりも突出させたことで、鋼矢板を地盤(特に支持層などの硬質な地盤)に打ち込む際に、閉合鋼材に作用する地盤抵抗によるモーメントに対し、鋼矢板本体の突出部が地盤に引っ掛かって回転抵抗として機能することで、鋼矢板本体に生じる曲げ応力を低減させることができるために、鋼矢板本体および閉合鋼材の変形をより効果的に防止することができ、鋼矢板を精度よく施工することができる。
Furthermore, in the steel sheet pile of this invention, it is preferable that the front-end | tip of the said steel sheet pile main body protrudes in the front-end | tip direction rather than the front-end | tip of the said closed steel material.
According to such a structure, when the steel sheet pile main body protrudes from the closed steel material, the ground resistance acting on the closed steel material when the steel sheet pile is driven into the ground (particularly a hard ground such as a support layer). Because the projecting part of the steel sheet pile main body is hooked on the ground and functions as rotational resistance against the moment caused by the above, it is possible to reduce the bending stress generated in the steel sheet pile main body. It can prevent effectively and can construct a steel sheet pile accurately.

一方、本発明の鋼矢板基礎構造は、前記いずれかの閉合鋼材を有した鋼矢板を含む複数の鋼矢板が平面多角形状に連結されるとともに、これらの鋼矢板の上部にコンクリート製フーチングが一体的に形成されたことを特徴とする。
このような本発明によれば、前述したように高い鉛直支持力を発揮できる鋼矢板によってコンクリート製フーチングの自重およびフーチングに作用する上部構造の荷重を確実に支持することができ、鋼矢板を用いた安価な基礎構造を構築することができる。
On the other hand, in the steel sheet pile foundation structure of the present invention, a plurality of steel sheet piles including a steel sheet pile having any one of the above-mentioned closed steel materials are connected in a planar polygonal shape, and a concrete footing is integrally formed on the upper part of these steel sheet piles. It is characterized by being formed.
According to the present invention as described above, the steel sheet pile capable of exhibiting a high vertical support force can surely support the weight of the concrete footing and the load of the superstructure acting on the footing. It is possible to build an inexpensive basic structure.

この際、本発明の鋼矢板基礎構造では、前記閉合鋼材を有した鋼矢板と前記閉合鋼材を有さない鋼矢板とが所定本数ごとに交互に連結され、前記閉合鋼材を有した鋼矢板の先端が地盤の支持層に貫入され、前記閉合鋼材を有さない鋼矢板の先端が前記支持層に貫入されるか、または前記支持層よりも上方位置で止められることが好ましい。
このような構成によれば、閉合鋼材を有した鋼矢板と閉合鋼材を有さない鋼矢板とを用い、閉合鋼材を有した鋼矢板を支持層に貫入させることで、前述のように高い先端支持力を得ることができる。一方、閉合鋼材を有さない鋼矢板に関しては、必要に応じて支持層に貫入させるか、または支持層よりも上方で止めることで、施工手間や鋼矢板の鋼材量を削減することができ、施工性や低コスト化を一層向上させることができる。
At this time, in the steel sheet pile foundation structure of the present invention, the steel sheet pile having the closed steel material and the steel sheet pile not having the closed steel material are alternately connected for each predetermined number of steel sheet piles having the closed steel material. It is preferable that a front end penetrates into the support layer of the ground, and a front end of the steel sheet pile without the closed steel material penetrates into the support layer or is stopped at a position higher than the support layer.
According to such a configuration, the steel sheet pile with the closed steel material and the steel sheet pile without the closed steel material are used, and the steel sheet pile with the closed steel material is inserted into the support layer, so that the high tip as described above. Support force can be obtained. On the other hand, for steel sheet piles that do not have a closed steel material, it is possible to reduce the construction labor and the amount of steel material of the steel sheet pile by penetrating into the support layer as needed or stopping above the support layer, Workability and cost reduction can be further improved.

以上のような本発明の鋼矢板および鋼矢板基礎構造によれば、鋼矢板の先端から所定の区間に閉合鋼材を配置したことで、鋼矢板の打設時の変形や損傷を抑制し、かつ飛躍的に高い支持力を確実に発揮させることができ、安価で優れた支持力を発揮する支持構造を構築することができる。   According to the steel sheet pile and steel sheet pile foundation structure of the present invention as described above, by disposing the closed steel material in the predetermined section from the tip of the steel sheet pile, it is possible to suppress deformation and damage at the time of placing the steel sheet pile, and It is possible to build a support structure that can reliably exhibit a significantly high support force and that is inexpensive and exhibits an excellent support force.

第1参考形態に係る鋼矢板を示す正面図および側面図である。It is the front view and side view which show the steel sheet pile which concerns on a 1st reference form. 前記第1参考形態の鋼矢板を示す断面図である。It is sectional drawing which shows the steel sheet pile of a said 1st reference form. 図2とは異なる前記第1参考形態の鋼矢板を示す断面図である。It is sectional drawing which shows the steel sheet pile of the said 1st reference form different from FIG. 第2参考形態に係る鋼矢板を示す正面図および側面図である。It is the front view and side view which show the steel sheet pile which concerns on a 2nd reference form. 前記第2参考実施形態の鋼矢板を示す断面図である。It is sectional drawing which shows the steel sheet pile of the said 2nd reference embodiment. 図5とは異なる前記第2参考形態の鋼矢板を示す断面図である。It is sectional drawing which shows the steel sheet pile of the said 2nd reference form different from FIG. 前記参考形態の鋼矢板を用いた支持力測定実験の結果を表すグラフである。It is a graph showing the result of the bearing capacity measurement experiment using the steel sheet pile of the said reference form. 本発明の第1実施形態に係る鋼矢板を示す正面図および側面図である。It is the front view and side view which show the steel sheet pile concerning 1st Embodiment of this invention. (E)は前記第1実施形態に係る鋼矢板を示す側面図であり、(A)〜(D)は前記参考形態における各種の鋼矢板を示す側面図である。(E) is a side view which shows the steel sheet pile which concerns on the said 1st Embodiment, (A)-(D) is a side view which shows the various steel sheet piles in the said reference form. 前記参考形態における図9とは異なる鋼矢板を示す側面図である。It is a side view which shows the steel sheet pile different from FIG. 9 in the said reference form. 本発明の変形例に係る鋼矢板の鋼矢板本体を示す正面図である。It is a front view which shows the steel sheet pile main body of the steel sheet pile concerning the modification of this invention. 本発明の変形例に係る鋼矢板の閉合鋼材を示す正面図である。It is a front view which shows the closed steel material of the steel sheet pile which concerns on the modification of this invention. 前記参考形態を適用した鋼矢板基礎構造を示す垂直方向の断面図である。It is sectional drawing of the perpendicular direction which shows the steel sheet pile foundation structure to which the said reference form is applied. 前記鋼矢板基礎構造を示す側面図である。It is a side view which shows the said steel sheet pile foundation structure. 前記鋼矢板基礎構造を示す水平方向の断面図である。It is sectional drawing of the horizontal direction which shows the said steel sheet pile foundation structure. 前記鋼矢板基礎構造の変形例を示す側面図である。It is a side view which shows the modification of the said steel sheet pile foundation structure.

以下、本発明の実施形態を図面に基づいて説明する。
図1は、本発明には含まれないが後述する本発明の実施形態で参照する第1参考形態に係る鋼矢板1を示す正面図および側面図である。図2は、前記第1参考形態の鋼矢板1を示す断面図であり、図2(A)は、図1に矢視IIA-IIA線で示す断面図であり、図2(B)は、図1に矢視IIB-IIB線で示す断面図である。図3は、図2とは異なる第1参考形態の鋼矢板1を示す断面図であり、図3(A)は、図1に矢視IIIA-IIIA線で示す断面図であり、図3(B)は、図1に矢視IIIB-IIIB線で示す断面図である。
図1〜図3において、鋼矢板1は、鋼矢板本体2と、この鋼矢板本体2の長手方向(軸方向)先端部(地盤に貫入される先端側)に接合された閉合鋼材3とを有して構成されている。
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a front view and a side view showing a steel sheet pile 1 according to a first reference embodiment which is not included in the present invention but is referred to in an embodiment of the present invention described later. 2 is a cross-sectional view showing the steel sheet pile 1 of the first reference embodiment, FIG. 2 (A) is a cross-sectional view taken along the line IIA-IIA in FIG. 1, and FIG. FIG. 2 is a cross-sectional view taken along line IIB-IIB in FIG. FIG. 3 is a cross-sectional view showing a steel sheet pile 1 of a first reference form different from FIG. 2, and FIG. 3 (A) is a cross-sectional view taken along the line IIIA-IIIA in FIG. B) is a cross-sectional view taken along line IIIB-IIIB in FIG.
1 to 3, a steel sheet pile 1 includes a steel sheet pile main body 2 and a closed steel material 3 joined to a longitudinal direction (axial direction) tip portion (tip end side penetrating into the ground) of the steel sheet pile main body 2. It is configured.

鋼矢板本体2は、図2および図3に示すように、熱間圧延で製造され、断面中央に位置するウェブ部21と、このウェブ部21の両端に連続して形成された一対のフランジ部22,22と、これら一対のフランジ部22,22の先端側に形成された継手部23,23とを有して形成されている。そして、図2に示す鋼矢板本体2(2A)は、所謂U形鋼矢板と呼ばれるもので、一対のフランジ部22,22の先端同士が略平行に設けられた略U字形の断面形状を有したものである。一方、図3に示す鋼矢板本体2(2B)は、所謂ハット形鋼矢板と呼ばれるもので、一対のフランジ部22,22の先端同士がハ字形に開くとともに、継手部23,23が側方に延びて設けられたハット形の断面形状を有したものである。これらの鋼矢板本体2(2A,2B)では、ウェブ部21からフランジ部22先端までのウェブ部21に直交する長さ寸法が、当該鋼矢板本体2の断面高さ寸法hとされている。   As shown in FIGS. 2 and 3, the steel sheet pile main body 2 is manufactured by hot rolling, and a web portion 21 located at the center of the cross section and a pair of flange portions formed continuously at both ends of the web portion 21. 22 and 22 and the joint parts 23 and 23 formed in the front end side of these pair of flange parts 22 and 22 are formed. The steel sheet pile main body 2 (2A) shown in FIG. 2 is a so-called U-shaped steel sheet pile, and has a substantially U-shaped cross-sectional shape in which the ends of the pair of flange portions 22 and 22 are provided substantially in parallel. It is a thing. On the other hand, the steel sheet pile main body 2 (2B) shown in FIG. 3 is a so-called hat-shaped steel sheet pile, and the ends of the pair of flange portions 22 and 22 open in a H-shape, and the joint portions 23 and 23 are formed laterally. It has a hat-shaped cross-sectional shape provided to extend. In these steel sheet pile main bodies 2 (2A, 2B), the length dimension orthogonal to the web portion 21 from the web portion 21 to the tip of the flange portion 22 is the cross-sectional height dimension h of the steel sheet pile main body 2.

閉合鋼材3は、鋼矢板本体2の長手方向先端部における一対のフランジ部22,22の先端間に渡り、鋼矢板本体2の開断面を閉じて閉断面を形成するように接合されている。そして、図2に示す閉合鋼材3(3A)は、U形鋼矢板である鋼矢板本体2Aを所定の長さ寸法Lに切断して形成されたものである。一方、図3に示す閉合鋼材3(3B)は、ハット形鋼矢板である鋼矢板本体2Bを所定の長さ寸法Lに切断するとともに、その継手部23,23を切断して断面略コ字形に形成されたものである。このような閉合鋼材3は、鋼矢板本体2のウェブ部21およびフランジ部22,22と面対称になるように、鋼矢板本体2の継手部23,23に溶接接合されている。また、閉合鋼材3における鋼矢板本体2の長手方向に沿った長さ寸法Lは、鋼矢板本体2の断面高さ寸法hに対して2倍以上かつ7倍以下(2.0h≦L≦7.0h)に設定されている。   The closed steel material 3 spans between the distal ends of the pair of flange portions 22, 22 at the longitudinal direction distal end portion of the steel sheet pile main body 2, and is joined so as to close the open cross section of the steel sheet pile main body 2 and form a closed cross section. And the closed steel material 3 (3A) shown in FIG. 2 is formed by cutting the steel sheet pile main body 2A, which is a U-shaped steel sheet pile, into a predetermined length L. On the other hand, the closed steel material 3 (3B) shown in FIG. 3 cuts the steel sheet pile main body 2B, which is a hat-shaped steel sheet pile, into a predetermined length L, and cuts the joint portions 23, 23 to obtain a substantially U-shaped cross section. It is formed. Such a closed steel material 3 is welded to the joint portions 23 and 23 of the steel sheet pile main body 2 so as to be in plane symmetry with the web portion 21 and the flange portions 22 and 22 of the steel sheet pile main body 2. Moreover, the length dimension L along the longitudinal direction of the steel sheet pile main body 2 in the closed steel material 3 is 2 times or more and 7 times or less with respect to the cross-sectional height dimension h of the steel sheet pile main body 2 (2.0 h ≦ L ≦ 7). .0h).

図4は、本発明には含まれないが後述する本発明の実施形態で参照する第2参考形態に係る鋼矢板1を示す正面図および側面図である。図5は、前記第2参考形態の鋼矢板1を示す断面図であり、図5(A)は、図4に矢視VA-VA線で示す断面図であり、図5(B)は、図4に矢視VB-VB線で示す断面図である。図6は、図5とは異なる第2参考形態の鋼矢板1を示す断面図であり、図6(A)は、図4に矢視VIA-VIA線で示す断面図であり、図6(B)は、図4に矢視VIB-VIB線で示す断面図である。
図4〜図6において、閉合鋼材3(3C)は、平板状の鋼板から構成され、鋼矢板本体2(2A,2B)のフランジ部22,22の先端間に渡り、鋼矢板本体2の開断面を閉じて閉断面を形成するように溶接接合されている。そして、閉合鋼材3における鋼矢板本体2の長手方向に沿った長さ寸法Lは、鋼矢板本体2の断面高さ寸法hに対して2倍以上かつ7倍以下(2.0h≦L≦7.0h)に設定されている。また、図5に示す鋼矢板本体2Aは、図2と同様のU形鋼矢板を用いたもので、図6に示す鋼矢板本体2Bは、図3と同様のハット形鋼矢板を用いたものである。
FIG. 4 is a front view and a side view showing a steel sheet pile 1 according to a second reference embodiment which is not included in the present invention but is referred to in an embodiment of the present invention described later. FIG. 5 is a cross-sectional view showing the steel sheet pile 1 of the second reference embodiment, FIG. 5 (A) is a cross-sectional view taken along the line VA-VA in FIG. 4, and FIG. FIG. 5 is a cross-sectional view taken along line VB-VB in FIG. 6 is a cross-sectional view showing a steel sheet pile 1 of a second reference form different from FIG. 5, and FIG. 6 (A) is a cross-sectional view taken along line VIA-VIA in FIG. FIG. 4B is a sectional view taken along line VIB-VIB in FIG.
4 to 6, the closed steel material 3 (3C) is composed of a flat steel plate, spans between the tips of the flange portions 22 and 22 of the steel sheet pile main body 2 (2A and 2B), and opens the steel sheet pile main body 2. It is welded to close the cross section to form a closed cross section. And the length dimension L along the longitudinal direction of the steel sheet pile main body 2 in the closed steel material 3 is 2 times or more and 7 times or less with respect to the cross-sectional height dimension h of the steel sheet pile main body 2 (2.0h <= L <= 7 .0h). Further, the steel sheet pile main body 2A shown in FIG. 5 uses a U-shaped steel sheet pile similar to FIG. 2, and the steel sheet pile main body 2B shown in FIG. 6 uses a hat-shaped steel sheet pile similar to FIG. It is.

以上の鋼矢板1を地盤に打設した際に得られる支持力(地盤抵抗)に関して実施した実験について図7に基づいて説明する。この実験では、前記閉合鋼材3の長さ寸法Lと鋼矢板本体2の断面高さ寸法hとの寸法比(L/h)を、0倍(つまり閉合鋼材3を設けない場合)から10倍まで(L/h=1.0,2.0,4.0,6.0,10)の各ケースについて実施した。
図7は,本実験の結果を表すグラフであって、横軸が閉合鋼材3の長さ寸法Lと鋼矢板本体2の断面高さ寸法hとの寸法比L/hで、縦軸が得られる支持力P(地盤抵抗)の最大支持力Pmに対する比P/Pmである。ここで、最大支持力Pmとしては、寸法比L/hが10倍(L/h=10)の場合の地盤抵抗値を用いた。
An experiment conducted on the supporting force (ground resistance) obtained when the steel sheet pile 1 is placed on the ground will be described with reference to FIG. In this experiment, the dimensional ratio (L / h) between the length dimension L of the closed steel material 3 and the cross-sectional height dimension h of the steel sheet pile main body 2 is increased from 0 times (that is, when the closed steel material 3 is not provided) to 10 times. (L / h = 1.0, 2.0, 4.0, 6.0, 10).
FIG. 7 is a graph showing the results of this experiment, in which the horizontal axis is the dimensional ratio L / h between the length dimension L of the closed steel material 3 and the cross-sectional height dimension h of the steel sheet pile main body 2, and the vertical axis is obtained. The ratio P / Pm of the support force P (ground resistance) to the maximum support force Pm. Here, as the maximum supporting force Pm, the ground resistance value when the dimensional ratio L / h is 10 times (L / h = 10) was used.

この実験結果から以下のことが判明した。
(1)閉合鋼材3を配置しない場合(すなわちL/h=0の場合)には、最大支持力Pmの約33%の支持力Pしか発揮しないが、閉合鋼材3の長さ寸法Lが長くなると支持力Pが次第に増加する。
(2)寸法比L/hが6.4倍以上(L/h≧6.4)の場合には、最大支持力Pmと同等の支持力Pを発揮することができる。
(3)寸法比L/hが1.0倍(L/h=1.0)の鋼矢板1では、寸法比L/hが2.0倍(L/h=2.0)の場合よりも大きな支持力Pを発揮したが、実験後に鋼矢板1を調査した結果、先端部分で折れ曲がりが発生していた。
以上の実験結果から、閉合鋼材3の長さ寸法Lが鋼矢板本体2の断面高さ寸法hの2倍よりも小さい(L/h<2.0)と、先端部での折れ曲がりの危険性があり、支持力Pを確実に発揮することができないことが明らかである。また、閉合鋼材3の長さ寸法Lを鋼矢板本体2の断面高さ寸法hの6.4倍以上としても、最大支持力Pm以上に支持力が増加しないことが明らかである。そして、閉合鋼材3は、部材を切断して溶接加工により配置されるものであるため、その長さ寸法Lを小さくすることが経済的であることから、余裕長を考慮して閉合鋼材3の長さ寸法Lは、鋼矢板本体2の断面高さ寸法hの7倍以下であることが最適である。
From the experimental results, the following was found.
(1) When the closed steel material 3 is not disposed (that is, when L / h = 0), only the support force P of about 33% of the maximum support force Pm is exhibited, but the length dimension L of the closed steel material 3 is long. Then, the supporting force P gradually increases.
(2) When the dimensional ratio L / h is 6.4 times or more (L / h ≧ 6.4), the support force P equivalent to the maximum support force Pm can be exhibited.
(3) In the steel sheet pile 1 with the dimensional ratio L / h of 1.0 times (L / h = 1.0), the dimensional ratio L / h is 2.0 times (L / h = 2.0). However, as a result of investigating the steel sheet pile 1 after the experiment, bending occurred at the tip portion.
From the above experimental results, when the length dimension L of the closed steel material 3 is smaller than twice the sectional height dimension h of the steel sheet pile main body 2 (L / h <2.0), there is a risk of bending at the tip portion. It is clear that the supporting force P cannot be exhibited reliably. Moreover, even if the length dimension L of the closed steel material 3 is set to 6.4 times or more of the cross-sectional height dimension h of the steel sheet pile main body 2, it is clear that the supporting force does not increase beyond the maximum supporting force Pm. And since the closed steel material 3 cut | disconnects a member and is arrange | positioned by welding process, since it is economical to make the length dimension L small, the allowance length is considered and the closed steel material 3 of The length dimension L is optimally 7 times or less the cross-sectional height dimension h of the steel sheet pile main body 2.

以上のような第1および第2参考形態の鋼矢板1によれば、以下の作用、効果が得られる。
すなわち、閉合鋼材3を鋼矢板本体2の先端部に接合して鋼矢板本体2の開断面を閉じて閉断面形状としたことで、鋼矢板1を地盤に打設した際に、閉断面部分に入り込んだ土塊が締め固められて鋼矢板1の先端部が閉塞されることによって、その先端閉塞部分の投影面積に応じた高い先端支持力を得ることができる。そして、閉合鋼材3の長さ寸法Lが鋼矢板本体2の断面高さ寸法hに対して2倍以上に設定されていることで、支持層などの硬質な地盤に鋼矢板1の先端部を打ち込む場合でも、閉合鋼材3のめくれ上がりが防止できるとともに、鋼矢板本体2の変形を防止して打設後の鉛直精度が確保できる。さらに、閉合鋼材3の長さ寸法Lが鋼矢板本体2の断面高さ寸法hに対して7倍以下に設定されていることで、打設時の摩擦抵抗を抑制して施工性を向上させることができる。従って、支持層としての硬質な地盤に確実に打設して高い先端支持力が得られることから、支持構造として利用する場合に確実な鉛直支持力を発揮させることができ、鋼矢板1を用いた安価な基礎構造を構築することができる。
According to the steel sheet pile 1 of the first and second reference forms as described above, the following actions and effects can be obtained.
That is, the closed steel material 3 is joined to the tip of the steel sheet pile main body 2 to close the open cross section of the steel sheet pile main body 2 to have a closed cross sectional shape. When the soil mass that has entered is compacted and the tip portion of the steel sheet pile 1 is closed, a high tip support force according to the projected area of the tip closing portion can be obtained. And since the length dimension L of the closed steel material 3 is set to 2 times or more with respect to the cross-sectional height dimension h of the steel sheet pile main body 2, the front-end | tip part of the steel sheet pile 1 is attached to hard grounds, such as a support layer. Even when driving, the closed steel material 3 can be prevented from turning up, and the steel sheet pile main body 2 can be prevented from being deformed to ensure vertical accuracy after placement. Furthermore, the length dimension L of the closed steel material 3 is set to 7 times or less with respect to the cross-sectional height dimension h of the steel sheet pile main body 2, thereby suppressing the frictional resistance at the time of placing and improving the workability. be able to. Therefore, since a high tip support force can be obtained by reliably placing on a hard ground as a support layer, a reliable vertical support force can be exhibited when used as a support structure, and the steel sheet pile 1 is used. It is possible to build an inexpensive basic structure.

図8は、本発明の第1実施形態に係る鋼矢板1を示す正面図および側面図である。
図8において、本実施形態の鋼矢板1は、前記第1または第2の参考形態と同様な基本構成を有するが、鋼矢板1の先端部、すなわち鋼矢板本体2の先端部および閉合鋼材3の先端部には、閉合鋼材3側から鋼矢板本体2側に向かって先端方向(下方)に傾斜した傾斜面24,31が形成されている。また、閉合鋼材3の上端部には、閉合鋼材3側から鋼矢板本体2側に向かって上方に傾斜した傾斜面32が形成されている。なお、図8に示す鋼矢板本体2は、図2と同様のU形鋼矢板(鋼矢板2A)を用いたものでもよく、図3と同様のハット形鋼矢板(鋼矢板2B)を用いたものでもよい。
FIG. 8 is a front view and a side view showing the steel sheet pile 1 according to the first embodiment of the present invention.
In FIG. 8, the steel sheet pile 1 of the present embodiment has the same basic configuration as the first or second reference embodiment, but the tip of the steel sheet pile 1, that is, the tip of the steel sheet pile main body 2 and the closed steel material 3. The inclined surfaces 24 and 31 that are inclined in the distal direction (downward) from the closed steel material 3 side toward the steel sheet pile main body 2 side are formed at the distal end portion. Moreover, the inclined surface 32 which inclined upwards toward the steel sheet pile main body 2 side from the closed steel material 3 side is formed in the upper end part of the closed steel material 3. In addition, the steel sheet pile main body 2 shown in FIG. 8 may use the same U-shaped steel sheet pile (steel sheet pile 2A) as FIG. 2, and used the hat-shaped steel sheet pile (steel sheet pile 2B) similar to FIG. It may be a thing.

次に、前記第1参考形態の鋼矢板1に傾斜面を形成した例を図9に示す。ここで、図9(A)は、前記第1参考形態の鋼矢板1の側面図であり、図9(B)は、鋼矢板本体2の先端部に傾斜面24を形成した鋼矢板1の側面図であり、図9(C)は、鋼矢板本体2の先端部および閉合鋼材3の先端部に傾斜面24,31を形成した鋼矢板1の側面図であり、図9(D)は、閉合鋼材3の先端部に傾斜面31を形成した鋼矢板1の側面図であり、図9(E)は、鋼矢板本体2の先端部および閉合鋼材3の先端部に傾斜面24,31を形成しかつ閉合鋼材3の上端部に傾斜面32を形成した鋼矢板1の側面図である。図9では、図9(E)の鋼矢板1が、本発明の実施形態である。
以上の各図に示されるように、鋼矢板本体2および閉合鋼材3の両方に傾斜面24,31が形成されてもよく、あるいは鋼矢板本体2および閉合鋼材3のいずれか一方に形成されてもよい。さらに、閉合鋼材3に傾斜面31および傾斜面31,32を形成する場合には、傾斜面31,32以外の直線部分の長さが前記長さ寸法L以上となるように設定されている。
Next, the example which formed the inclined surface in the steel sheet pile 1 of the said 1st reference form is shown in FIG. Here, FIG. 9 (A) is a side view of the steel sheet pile 1 of the first reference embodiment, and FIG. 9 (B) is a view of the steel sheet pile 1 in which the inclined surface 24 is formed at the tip of the steel sheet pile main body 2. FIG. 9C is a side view of the steel sheet pile 1 in which the inclined surfaces 24 and 31 are formed on the distal end portion of the steel sheet pile main body 2 and the distal end portion of the closed steel material 3, and FIG. FIG. 9E is a side view of the steel sheet pile 1 in which the inclined surface 31 is formed at the distal end portion of the closed steel material 3, and FIG. 9E shows the inclined surfaces 24 and 31 at the distal end portion of the steel sheet pile main body 2 and the distal end portion of the closed steel material 3. 1 is a side view of a steel sheet pile 1 in which an inclined surface 32 is formed at the upper end of the closed steel material 3. In FIG. 9, the steel sheet pile 1 of FIG. 9 (E) is an embodiment of the present invention.
As shown in each of the above figures, the inclined surfaces 24 and 31 may be formed on both the steel sheet pile main body 2 and the closed steel material 3, or may be formed on either the steel sheet pile main body 2 or the closed steel material 3. Also good. Furthermore, when forming the inclined surface 31 and the inclined surfaces 31 and 32 in the closed steel material 3, it sets so that the length of the linear part other than the inclined surfaces 31 and 32 may become the said length dimension L or more.

また、前記第2参考形態の鋼矢板1に傾斜面を形成した例を図10に示す。ここで、図10(A)は、前記第2参考形態の鋼矢板1の側面図であり、図10(B)は、鋼矢板本体2の先端部に傾斜面24を形成した鋼矢板1の側面図である。この図10に示す鋼矢板1においても、閉合鋼材3の長さが前記長さ寸法L以上となるように設定されている。
さらに、鋼矢板1において、鋼矢板本体2の先端が閉合鋼材3の先端よりも下方に突出して形成されていてもよい。この場合、下方に突出した鋼矢板本体2の先端に図9(B),(C),(E)あるいは図10(B)のように、傾斜面24が形成されていてもよいし、図1や図4のように、傾斜面24が形成されずに略水平に切断されていてもよい。
Moreover, the example which formed the inclined surface in the steel sheet pile 1 of the said 2nd reference form is shown in FIG. Here, FIG. 10 (A) is a side view of the steel sheet pile 1 of the second reference embodiment, and FIG. 10 (B) is a view of the steel sheet pile 1 in which the inclined surface 24 is formed at the tip of the steel sheet pile main body 2. It is a side view. Also in the steel sheet pile 1 shown in FIG. 10, the length of the closed steel material 3 is set to be equal to or longer than the length dimension L.
Further, in the steel sheet pile 1, the tip end of the steel sheet pile main body 2 may be formed so as to protrude downward from the tip end of the closed steel material 3. In this case, an inclined surface 24 may be formed at the tip of the steel sheet pile main body 2 protruding downward as shown in FIGS. 9 (B), (C), (E) or FIG. 10 (B). As shown in FIG. 1 and FIG. 4, the inclined surface 24 may be cut substantially horizontally without being formed.

以上のような第1実施形態の鋼矢板1によれば、前記第1および第2の参考形態で得られる作用、効果に加えて、以下の作用、効果が得られる。
すなわち、鋼矢板1を地中に打設する際に鋼矢板本体2に作用する曲げモーメントを低減させることができ、鋼矢板1の先端部に変形や折れ曲がりを防止しつつ施工することができるために、鋼矢板1の施工精度を向上させることができる。具体的には、鋼矢板1の先端閉塞部分に作用する上向きの地盤抵抗と鋼矢板1の施工荷重力とが偏心することから閉合鋼材3の上部位置における鋼矢板本体2に曲げモーメントが作用することになる。しかし、鋼矢板1の先端部に傾斜面24,31を形成したことで、この傾斜面24,31に作用する斜め上向きの地盤抵抗によって、前記偏心による曲げモーメントを打ち消す方向に作用する曲げモーメントが生じ、これによって鋼矢板本体2に作用する曲げモーメントを低減させることができる。
さらに、鋼矢板本体2の先端が閉合鋼材3の先端よりも下方に突出して形成されていれば、この突出した鋼矢板本体2の先端が地盤に引っ掛かって回転抵抗として機能することで、前記偏心による曲げモーメントに抵抗することができ、鋼矢板本体2に生じる曲げ応力を低減させて鋼矢板本体2や閉合鋼材3の変形をより効果的に防止することができる。
また、図9(E)および図8(A),(B)に示すように、閉合鋼材3の上端部に傾斜面32が形成されていると、曲げ変形に抵抗する補強リブとして作用するために、鋼矢板本体2や閉合鋼材3の折れ曲がりを抑制することができる。
According to the steel sheet pile 1 of the first embodiment as described above, the following actions and effects are obtained in addition to the actions and effects obtained in the first and second reference forms.
That is, since the bending moment acting on the steel sheet pile main body 2 can be reduced when the steel sheet pile 1 is placed in the ground, the steel sheet pile 1 can be constructed while preventing deformation and bending. Moreover, the construction accuracy of the steel sheet pile 1 can be improved. Specifically, since the upward ground resistance acting on the closed end portion of the steel sheet pile 1 and the construction load force of the steel sheet pile 1 are eccentric, a bending moment acts on the steel sheet pile main body 2 at the upper position of the closed steel material 3. It will be. However, since the inclined surfaces 24 and 31 are formed at the tip of the steel sheet pile 1, the bending moment acting in the direction to cancel the bending moment due to the eccentricity is caused by the obliquely upward ground resistance acting on the inclined surfaces 24 and 31. As a result, the bending moment acting on the steel sheet pile main body 2 can be reduced.
Furthermore, if the front end of the steel sheet pile main body 2 is formed so as to protrude downward from the front end of the closed steel material 3, the protruding front end of the steel sheet pile main body 2 is caught on the ground and functions as a rotational resistance. It is possible to resist the bending moment caused by the above, and it is possible to reduce the bending stress generated in the steel sheet pile main body 2 and to prevent the deformation of the steel sheet pile main body 2 and the closed steel material 3 more effectively.
Further, as shown in FIGS. 9 (E) and 8 (A), 8 (B), when the inclined surface 32 is formed at the upper end portion of the closed steel material 3, it acts as a reinforcing rib that resists bending deformation. In addition, the bending of the steel sheet pile main body 2 and the closed steel material 3 can be suppressed.

また、本発明の鋼矢板1において、鋼矢板本体2および閉合鋼材3には、以下の図11、図12に示すような突起25,32,33が形成されていることが好ましい。ここで、図11は、前記実施形態の変形例に係る鋼矢板1の鋼矢板本体2を示す正面図である。図12は、変形例に係る鋼矢板1の閉合鋼材3を示す正面図である。
図11において、鋼矢板本体2の先端部におけるウェブ部21の内面、つまり閉合鋼材3と対向する側の面には、複数の棒状鋼材を溶接固定した突起25が形成されている。これらの突起25は、閉合鋼材3の長さ寸法Lの範囲内、つまり鋼矢板1を地盤に打設した際に先端閉塞部分となる位置に設けられ、鋼矢板本体2の長手方向に直交して形成されている。
一方、図12において、閉合鋼材3の内面、つまり鋼矢板本体2のウェブ部21と対向する側の面には、転造により形成した複数の平行線状の突起32(図12(A))、あるいは転造により形成した複数のチェッカー状突起33(図12(B))が形成されている。なお、図12(A)に示す閉合鋼材3の平行線状の突起としては、棒状鋼材を溶接固定したものでもよい。
以上のような突起25,32,33が形成されていれば、地盤との摩擦力が増加するために、地盤の閉塞性がさらに向上して先端支持力を確実に発揮させることができる。
Moreover, in the steel sheet pile 1 of this invention, it is preferable that the protrusions 25, 32, and 33 as shown in the following FIGS. 11 and 12 are formed in the steel sheet pile main body 2 and the closed steel material 3. Here, FIG. 11 is a front view showing the steel sheet pile main body 2 of the steel sheet pile 1 according to the modification of the embodiment. FIG. 12 is a front view showing the closed steel material 3 of the steel sheet pile 1 according to the modification.
In FIG. 11, protrusions 25 are formed by welding and fixing a plurality of rod-shaped steel materials on the inner surface of the web portion 21 at the tip of the steel sheet pile main body 2, that is, the surface facing the closed steel material 3. These protrusions 25 are provided within the range of the length dimension L of the closed steel material 3, that is, at a position that becomes a closed end portion when the steel sheet pile 1 is driven on the ground, and are orthogonal to the longitudinal direction of the steel sheet pile main body 2. Is formed.
On the other hand, in FIG. 12, on the inner surface of the closed steel material 3, that is, the surface facing the web portion 21 of the steel sheet pile main body 2, a plurality of parallel line-shaped protrusions 32 (FIG. 12 (A)) formed by rolling. Alternatively, a plurality of checker-like protrusions 33 (FIG. 12B) formed by rolling are formed. In addition, as a parallel line-shaped protrusion of the closed steel material 3 shown in FIG. 12 (A), a rod-shaped steel material welded and fixed may be used.
If the projections 25, 32, and 33 as described above are formed, the frictional force with the ground increases, so that the closing performance of the ground can be further improved and the tip support force can be reliably exhibited.

次に、本発明の鋼矢板基礎構造について、前記参考形態を参照しながら図13〜図16に基づいて説明する。
図13は、鋼矢板基礎構造を示す垂直方向の断面図であり、図14は、鋼矢板基礎構造を示す側面図である。図15は、鋼矢板基礎構造を示す水平方向の断面図である。図16は、鋼矢板基礎構造の変形例を示す側面図である。
図13〜図15において、鋼矢板基礎構造は、前記第1〜第2の参考形態または第1実施形態の鋼矢板1と、他の形態の鋼矢板1Aとを含む複数の鋼矢板1,1Aを地盤Gに貫入するとともに平面多角形状に連結した上部に、コンクリート製フーチングFを一体的に構築して構成され、フーチングFの上側に構築される橋脚等の上部構造Sの荷重を支持するものである。ここで、他の形態の鋼矢板1Aとしては、前記鋼矢板1の鋼矢板本体2のみから構成され、つまり閉合鋼材3が接合されていない通常のU形鋼矢板やハット形鋼矢板である。そして、本実施形態では、閉合鋼材3を有した鋼矢板1と、閉合鋼材3を有さない鋼矢板1Aとが1枚ごとに交互に連結されるとともに、これらの鋼矢板1,1Aの先端が地盤Gにおける支持層G1に貫入されており、この支持層G1への貫入深さは、前記閉合鋼材3の長さ寸法Lと略同一か、閉合鋼材3の長さ寸法L以上に設定されている。
一方、図16に示す鋼矢板基礎構造では、閉合鋼材3を有した鋼矢板1の先端は、支持層G1に貫入されるものの、閉合鋼材3を有さない鋼矢板1Aの先端は、支持層G1に貫入されずに、支持層G1よりも上方位置(例えば、中間層)で止められている。
Next, the steel sheet pile foundation structure of this invention is demonstrated based on FIGS. 13-16, referring the said reference form.
FIG. 13 is a vertical sectional view showing the steel sheet pile foundation structure, and FIG. 14 is a side view showing the steel sheet pile foundation structure. FIG. 15 is a horizontal cross-sectional view showing a steel sheet pile foundation structure. FIG. 16 is a side view showing a modification of the steel sheet pile foundation structure.
13 to 15, the steel sheet pile foundation structure includes a plurality of steel sheet piles 1, 1 </ b> A including the steel sheet pile 1 of the first to second reference forms or the first embodiment and the steel sheet pile 1 </ b> A of another form. Is constructed by integrally constructing a concrete footing F on the upper part that is inserted into the ground G and connected in a planar polygonal shape, and supports the load of the upper structure S such as a pier constructed on the upper side of the footing F It is. Here, as a steel sheet pile 1A of another form, it is comprised only from the steel sheet pile main body 2 of the said steel sheet pile 1, ie, the normal U-shaped steel sheet pile and hat-shaped steel sheet pile to which the closed steel material 3 is not joined. And in this embodiment, while the steel sheet pile 1 which has the closed steel material 3, and the steel sheet pile 1A which does not have the closed steel material 3 are connected alternately for every sheet | seat, the front-end | tip of these steel sheet piles 1 and 1A Is penetrated into the support layer G1 in the ground G, and the penetration depth into the support layer G1 is set to be substantially the same as the length dimension L of the closed steel material 3 or larger than the length dimension L of the closed steel material 3. ing.
On the other hand, in the steel sheet pile foundation structure shown in FIG. 16, the tip of the steel sheet pile 1 having the closed steel material 3 penetrates the support layer G1, but the tip of the steel sheet pile 1A not having the closed steel material 3 is the support layer. Without being penetrated into G1, it is stopped at a position above the support layer G1 (for example, an intermediate layer).

以上のような鋼矢板基礎構造によれば、以下の作用、効果が得られる。
すなわち、前述したように鋼矢板1によって高い支持力が得られることから、従来の鋼矢板を連続閉合した基礎構造と比較して、飛躍的に大きな支持力を発揮することができるために、基礎構造の寸法(例えば、フーチングFの底面積)を縮小することができ、基礎の施工スペースの縮小を図るとともに、施工コストを縮減することができる。さらに、基礎構造として必要な支持力が確保可能なように、閉合鋼材3を有する鋼矢板1を適宜用いることにより、さらに経済性に優れる基礎構造を提供することができる。閉合鋼材3を有さない鋼矢板1Aの先端を中間層で止めるようにすれば、その打設に要する施工手間や施工コスト、材料コストを節約することができるとともに、硬質な支持層G1への打設に伴う鋼矢板1Aの変形を防止して施工精度を向上させることができる。
According to the steel sheet pile foundation structure as described above, the following actions and effects can be obtained.
That is, as described above, since the steel sheet pile 1 can provide a high support force, it can exhibit a tremendously large support force as compared with a foundation structure in which a conventional steel sheet pile is continuously closed. The dimensions of the structure (for example, the bottom area of the footing F) can be reduced, the construction space for the foundation can be reduced, and the construction cost can be reduced. Further, by appropriately using the steel sheet pile 1 having the closed steel material 3 so that the necessary supporting force can be secured as the foundation structure, a foundation structure that is further excellent in economic efficiency can be provided. If the tip of the steel sheet pile 1A that does not have the closed steel material 3 is stopped by the intermediate layer, it is possible to save the construction labor, construction cost, and material cost required for the placement, and to the hard support layer G1. The construction accuracy can be improved by preventing the deformation of the steel sheet pile 1A due to the placing.

なお、本発明は、前記実施形態に限定されるものではなく、本発明の目的を達成できる他の構成等を含み、以下に示すような変形等も本発明に含まれる。
例えば、前記実施形態においては、鋼矢板1の鋼矢板本体2としてU形鋼矢板やハット形鋼矢板を利用したが、鋼矢板本体2に用いる鋼矢板は、ウェブ部21、フランジ部22および継手部23を有したものであればよく、その形態は特に限定されない。また、閉合鋼板3に用いる部材も、U形鋼矢板やハット形鋼矢板を用いた閉合鋼材3A,3Bや、平板状の鋼板からなる閉合鋼材3Cに限らず、任意の形態のものが利用可能である。
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 said embodiment, although the U-shaped steel sheet pile and the hat-shaped steel sheet pile were utilized as the steel sheet pile main body 2 of the steel sheet pile 1, the steel sheet pile used for the steel sheet pile main body 2 is the web part 21, the flange part 22, and the joint. What is necessary is just to have the part 23, and the form is not specifically limited. Moreover, the member used for the closed steel plate 3 is not limited to the closed steel materials 3A and 3B using a U-shaped steel sheet pile or a hat-shaped steel sheet pile, or the closed steel material 3C made of a flat steel plate. It is.

その他、本発明を実施するための最良の構成、方法などは、以上の記載で開示されているが、本発明は、これに限定されるものではない。すなわち、本発明は、主に特定の実施形態に関して特に図示され、かつ説明されているが、本発明の技術的思想および目的の範囲から逸脱することなく、以上述べた実施形態に対し、形状、材質、数量、その他の詳細な構成において、当業者が様々な変形を加えることができるものである。
従って、上記に開示した形状、材質などを限定した記載は、本発明の理解を容易にするために例示的に記載したものであり、本発明を限定するものではないから、それらの形状、材質などの限定の一部もしくは全部の限定を外した部材の名称での記載は、本発明に含まれるものである。
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.

1,1A…鋼矢板、2,2A,2B…鋼矢板本体、3,3A,3B,3C…閉合鋼材、21…ウェブ部、22…フランジ部、23…継手部、24,31,32…傾斜面、25,32,33…突起、L…閉合鋼材の長さ寸法、h…鋼矢板本体の断面高さ寸法、F…フーチング、G…地盤、G1…支持層、S…上部構造。   DESCRIPTION OF SYMBOLS 1,1A ... Steel sheet pile, 2, 2A, 2B ... Steel sheet pile main body, 3, 3A, 3B, 3C ... Closure steel material, 21 ... Web part, 22 ... Flange part, 23 ... Joint part, 24, 31, 32 ... Inclination Surface, 25, 32, 33 ... projection, L ... length dimension of closed steel material, h ... section height dimension of steel sheet pile main body, F ... footing, G ... ground, G1 ... support layer, S ... superstructure.

Claims (3)

ウェブ部と、このウェブ部の両端に連続して形成された一対のフランジ部と、これら一対のフランジ部の先端側に形成された継手部とを有した鋼矢板本体と、
前記鋼矢板本体の長手方向先端部における前記一対のフランジ部の先端間に渡って接合され、当該鋼矢板本体の開断面を閉じる閉合鋼材とを備え、
前記閉合鋼材の前記鋼矢板本体の長手方向に沿った長さ寸法が、前記ウェブ部からフランジ部先端までの当該鋼矢板本体の断面高さ寸法に対して2倍以上に設定され、
前記閉合鋼材の前記長手方向先端と反対側の上端部に形成され、当該閉合鋼材から鋼矢板本体に向かって傾斜した傾斜面が形成されていることを特徴とする鋼矢板。
A steel sheet pile main body having a web portion, a pair of flange portions formed continuously at both ends of the web portion, and a joint portion formed on the distal end side of the pair of flange portions;
The steel sheet pile main body is joined across the distal ends of the pair of flange portions in the longitudinal direction front end portion, and includes a closed steel material that closes the open cross section of the steel sheet pile main body,
The length dimension along the longitudinal direction of the steel sheet pile main body of the closed steel material is set to at least twice the cross-sectional height dimension of the steel sheet pile main body from the web portion to the flange portion tip,
A steel sheet pile having an inclined surface formed at an upper end portion of the closed steel material opposite to the front end in the longitudinal direction and inclined from the closed steel material toward the steel sheet pile main body.
請求項1に記載の閉合鋼材を有した鋼矢板を含む複数の鋼矢板が平面多角形状に連結されるとともに、これらの鋼矢板の上部にコンクリート製フーチングが一体的に形成されたことを特徴とする鋼矢板基礎構造。   A plurality of steel sheet piles including steel sheet piles having the closed steel material according to claim 1 are connected to each other in a planar polygonal shape, and concrete footings are integrally formed on top of these steel sheet piles. Steel sheet pile foundation structure. 請求項2に記載の鋼矢板基礎構造において、
前記閉合鋼材を有した鋼矢板と前記閉合鋼材を有さない鋼矢板とが所定本数ごとに交互に連結され、前記閉合鋼材を有した鋼矢板の先端が地盤の支持層に貫入され、
前記閉合鋼材を有さない鋼矢板の先端が前記支持層に貫入されるか、または前記支持層よりも上方位置で止められることを特徴とする鋼矢板基礎構造。
In the steel sheet pile foundation structure according to claim 2,
Steel sheet piles having the closed steel material and steel sheet piles not having the closed steel material are alternately connected every predetermined number, and the tip of the steel sheet pile having the closed steel material is penetrated into the support layer of the ground,
A steel sheet pile foundation structure, wherein a tip of a steel sheet pile not having the closed steel material is inserted into the support layer or stopped at a position higher than the support layer.
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