JP6860895B2 - Retaining wall and its construction method - Google Patents

Retaining wall and its construction method Download PDF

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JP6860895B2
JP6860895B2 JP2019057787A JP2019057787A JP6860895B2 JP 6860895 B2 JP6860895 B2 JP 6860895B2 JP 2019057787 A JP2019057787 A JP 2019057787A JP 2019057787 A JP2019057787 A JP 2019057787A JP 6860895 B2 JP6860895 B2 JP 6860895B2
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嘉津博 鹿糠
嘉津博 鹿糠
茂 田子
茂 田子
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株式会社カヌカデザイン
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本発明は、擁壁及びその施工方法に関するものであり、より詳細には、大型フーチング、バットレス、錘形基礎等を備えずに高い安定性及び剛性を発揮することができる擁壁及びその施工方法に関するものである。 The present invention relates to a retaining wall and its construction method, and more specifically, a retaining wall and its construction method capable of exhibiting high stability and rigidity without providing a large footing, a buttress, a pyramidal foundation, or the like. It is about.

高さ2mを超える切土、或いは、高さ1mを超える盛土等によって生じる崖や、急傾斜地又は水路等の如く高低差が生じる地盤においては、地盤の崩壊を阻止すべく擁壁を設置する必要が生じる。擁壁は、鉄筋コンクリート構造の壁体、或いは、プレキャストコンクリート製品又はコンクリートブロック等を組積した壁体からなる。 Retaining walls need to be installed to prevent the collapse of the ground on cliffs caused by cuts with a height of more than 2 m or embankments with a height of more than 1 m, or on ground with height differences such as steep slopes or waterways. Occurs. The retaining wall is composed of a wall body having a reinforced concrete structure, or a wall body in which precast concrete products, concrete blocks, etc. are assembled.

このような擁壁は、通常は、全体的にL字型断面又は逆T字型断面に設計され、比較的大型の基礎フーチングが擁壁底部に形成される。基礎フーチングは、擁壁に作用する荷重(土圧)及び擁壁の自重を支持地盤に伝達する広範な施工面積を確保するとともに、擁壁の転倒を防止するように機能する。 Such retaining walls are usually designed to have an overall L-shaped or inverted T-shaped cross section, with a relatively large foundation footing formed at the bottom of the retaining wall. The foundation footing functions to secure a wide construction area for transmitting the load (earth pressure) acting on the retaining wall and the weight of the retaining wall to the supporting ground, and to prevent the retaining wall from tipping over.

基礎フーチングは、高地盤側に比較的大きく延びるので、擁壁施工時に高地盤を広範囲に掘削し、擁壁施工後に掘削部分を埋め戻し土で埋め戻す必要が生じる。しかし、広範な高地盤の掘削及び埋め戻しは、多大な掘削工事の労力、移動土量の増加、埋め戻し土の非安定性等の問題を生じさせる。また、一般には、大型の基礎フーチングは、厚さ500mm〜600mm程度のコンクリート版からなり、施工において多量のコンクリート及び鉄筋を使用する必要があるので、多額の工事費を要する傾向がある。更には、施工現場の環境、条件又は地形によっては、大型の基礎フーチングを施工し難い状態が生じることもある。 Since the foundation footing extends relatively large toward the high ground side, it is necessary to excavate the high ground extensively during the retaining wall construction and backfill the excavated part with backfill soil after the retaining wall construction. However, extensive excavation and backfilling of high ground causes problems such as a large amount of excavation work effort, an increase in the amount of moving soil, and instability of backfill soil. Further, in general, a large foundation footing is made of a concrete slab having a thickness of about 500 mm to 600 mm, and it is necessary to use a large amount of concrete and reinforcing bars in the construction, so that a large amount of construction cost tends to be required. Furthermore, depending on the environment, conditions or terrain of the construction site, it may be difficult to construct a large foundation footing.

このような基礎フーチング施工の問題を解消すべく、支柱を構成する鋼製親杭に予め非転倒側の曲げモーメント(安定モーメント)を付与するように構成された乾式工法の擁壁構造が、特許第2824217号掲載公報に開示されている。 In order to solve such problems of foundation footing construction, the retaining wall structure of the dry construction method, which is configured to give a bending moment (stability moment) on the non-overturning side in advance to the steel main piles that make up the columns, has been patented. It is disclosed in the publication of No. 2824217.

本発明者は、このような擁壁構造において、杭の直上に配置された鉄筋コンクリート構造の立柱と、壁体の鉛直荷重を支持する鉄筋コンクリート構造の地中梁形基礎とを一体化するとともに、鉄筋コンクリート構造のバットレスを擁壁の背後に突設し、地中梁形態の錘形基礎をバットレス先端部に連結した構成を有する擁壁を特開2006-291575号公報及び特開2011-236571号公報等において提案している。 In such a retaining wall structure, the present inventor integrates a vertical column of a reinforced concrete structure arranged directly above a pile and an underground beam-shaped foundation of a reinforced concrete structure that supports a vertical load of a wall body, and also integrates the reinforced concrete. Retaining walls having a structure in which a buttress having a structure is projected behind the retaining wall and a pyramid-shaped foundation in the form of an underground beam is connected to the tip of the buttress are published in JP-A-2006-291575, JP-A-2011-236571, etc. Proposed in.

このように鉄筋コンクリート構造のバットレス及び錘形基礎を備えた擁壁においては、バットレス及び錘形基礎の自重によって擁壁の重心を高地盤側に変位させるとともに、バットレス壁面及び地盤の間の摩擦力や、錘形基礎及び地盤の間の摩擦力によって擁壁の転倒を効果的に阻止することができる。 In this way, in a retaining wall provided with a buttress and a pyramidal foundation having a reinforced concrete structure, the center of gravity of the retaining wall is displaced toward the high ground by the weight of the buttress and the pyramid foundation, and the frictional force between the buttress wall surface and the ground is also observed. , The frictional force between the pyramidal foundation and the ground can effectively prevent the retaining wall from tipping over.

また、本発明者は、コンクリート打設型枠として使用可能な矢板を高地盤に埋入して鉄筋コンクリート構造の壁体を施工するとともに、擁壁の壁芯位置に配置された鋼管杭によって壁体を支持する擁壁構造を特開2007-308876号公報等において提案している。 In addition, the present inventor embeds a sheet pile that can be used as a concrete casting formwork in the high ground to construct a wall body with a reinforced concrete structure, and also uses steel pipe piles arranged at the wall core position of the retaining wall to form the wall body. A retaining wall structure supporting the above is proposed in Japanese Patent Application Laid-Open No. 2007-308876.

特許第2824217号掲載公報Publication of Patent No. 2824217 特開2006-291575号公報Japanese Unexamined Patent Publication No. 2006-291575 特開2011-236571号公報Japanese Unexamined Patent Publication No. 2011-236571 特開2007-308876号公報Japanese Unexamined Patent Publication No. 2007-308876

バットレスや、錘形基礎等を用いた前述の擁壁構造によれば、大形基礎フーチングを備えた従来の擁壁構造に比べ、掘削土量の低減、工事作業の軽減等を図ることができる。しかしながら、この擁壁構造においては、バットレス又は錘形基礎が高地盤に比較的大きく延入するので、高地盤に建設すべき建築物又は構造物の配置又は構造等がバットレス又は錘形基礎等によって設計上の制限又は制約を受けるという問題が生じ易い。 According to the above-mentioned retaining wall structure using a buttress or a pyramid-shaped foundation, it is possible to reduce the amount of excavated soil, reduce the construction work, etc., as compared with the conventional retaining wall structure equipped with a large foundation footing. .. However, in this retaining wall structure, the buttress or pyramidal foundation extends relatively large to the high ground, so that the arrangement or structure of the building or structure to be constructed on the high ground is determined by the buttress or pyramidal foundation or the like. Problems of being subject to design restrictions or restrictions are likely to occur.

また、コンクリート打設型枠として使用可能な矢板を高地盤に埋入し且つ鋼管杭によって鉄筋コンクリート構造の壁体を支持する擁壁構造によれば、バットレス又は錘形基礎等が高地盤に設置されず、従って、擁壁の構造が高地盤の建築物又は構造物の設計に実質的に影響するのを回避し得る。しかしながら、この擁壁構造においては、高地盤掘削工事の前に矢板及び綱管杭を高地盤に埋入する必要があるので、このような施工形態を採用し難い敷地においては、この構成の擁壁は、施工し難い。また、この擁壁構造では、擁壁の安定モーメントを十分に確保し難く、水平土圧に対する鋼管杭の負荷が増大する。 In addition, according to the retaining wall structure in which a sheet pile that can be used as a concrete casting formwork is embedded in the high ground and the wall body of the reinforced concrete structure is supported by steel pipe piles, a buttress or a pyramid foundation is installed in the high ground. Therefore, it can be avoided that the structure of the retaining wall substantially affects the design of the high ground building or structure. However, in this retaining wall structure, it is necessary to embed sheet piles and rope piles in the high ground before the high ground excavation work. The wall is difficult to construct. Further, in this retaining wall structure, it is difficult to secure a sufficient stabilizing moment of the retaining wall, and the load of the steel pipe pile against the horizontal earth pressure increases.

本発明は、このような課題に鑑みてなされたものであり、その目的とするところは、大形基礎フーチングの施工を省略し、施工の容易性、工期の短縮、掘削土量の削減、コンクリート量及び鉄筋量の削減、工事費の低廉化等を図り、しかも、バットレス又は錘形基礎等を高地盤に設置せず、高地盤掘削工事の前に矢板及び綱管杭を高地盤に埋入することもなく施工することができ、加えて、水平土圧に対する鋼管杭の負荷を軽減することができる擁壁及びその施工方法を提供することにある。 The present invention has been made in view of such problems, and an object of the present invention is to omit the construction of a large foundation footing, to facilitate the construction, shorten the construction period, reduce the amount of excavated earth, and concrete. In order to reduce the amount and amount of reinforcing bars, reduce the construction cost, etc., and do not install batless or pyramidal foundations on the high ground, and embed sheet piles and rope piles in the high ground before the high ground excavation work. It is an object of the present invention to provide a retaining wall and a method of constructing the retaining wall, which can be constructed without any work and can reduce the load of the steel pipe pile against the horizontal earth pressure.

上記目的を達成すべく、本発明は、土留め壁を構成する鉄筋コンクリート構造の壁体と、上端部を前記壁体に埋込まれ、該壁体の自重を支持する鋼管杭とを有する擁壁において、
前記壁体の壁厚方向又は該壁体の壁芯と直交する方向に前記鋼管杭から間隔を隔てて前記壁体の高地盤側に配置され、水平土圧に抗する安定モーメントをその引抜き耐力によって擁壁に与える摩擦杭と、
前記壁体の下端部から高地盤側に一体的に延出又は突出し、該壁体に作用する転倒モーメントを前記摩擦杭の杭頭部に伝達する鉄筋コンクリート構造の地中梁とを有し、
該地中梁は、鉄筋をコンクリート内に配筋してなる梁主筋及びスタラップ筋を有し、前記摩擦杭の杭頭部は、前記地中梁に埋入し、該地中梁に固定されていることを特徴とする擁壁を提供する。
In order to achieve the above object, the present invention has a retaining wall having a wall body having a reinforced concrete structure constituting a retaining wall and a steel pipe pile having an upper end embedded in the wall body to support its own weight. In
It is arranged on the high ground side of the wall body at a distance from the steel pipe pile in the wall thickness direction of the wall body or in the direction orthogonal to the wall core of the wall body, and its pull-out strength withstands a stable moment against horizontal earth pressure. The friction stakes given to the retaining wall by
The integrally to extend or protrude from the lower end of the wall to a high ground side, and a ground beam of reinforced concrete structure for transmitting the overturning moment acting on the wall body pile head of the friction piles,
該地center sill is Rebar has a beam main reinforcements and Sturup muscle formed by Haisuji in the concrete, pile head of the friction piles, and embedded in the ground beam, is fixed to the ground beam It provides a retaining wall characterized by being.

本発明は又、上記構成の擁壁の施工方法であって、
高地盤を掘削し、前記壁体及び地中梁を施工可能な水平地盤面を形成する掘削・整地工程と、
前記鋼管杭及び摩擦杭を前記水平地盤面に施工し、該鋼管杭及び摩擦杭の上部を前記水平地盤面から上方に突出させる杭打ち工程と、
前記壁体及び地中梁の配筋・型枠工程と、
前記壁体及び地中梁のコンクリート打設工程と、
前記壁体と高地盤面との間に形成された作業空間に埋め戻し土を埋め戻す埋め戻し工程とを有することを特徴とする擁壁の施工方法を提供する。
The present invention is also a method of constructing a retaining wall having the above configuration.
Excavation and grading process to excavate high ground and form a horizontal ground surface on which the wall body and underground beam can be constructed,
A pile driving step of constructing the steel pipe pile and the friction pile on the horizontal ground surface and projecting the upper part of the steel pipe pile and the friction pile upward from the horizontal ground surface.
Reinforcement / formwork process of the wall body and underground beam,
The concrete placing process of the wall body and the underground beam, and
Provided is a method for constructing a retaining wall, which comprises a backfilling step of backfilling backfilling soil in a working space formed between the wall body and a highland surface.

本発明の上記構成によれば、擁壁は、壁体の自重(鉛直荷重)を支持する鋼管杭と、鋼管杭の背後に配置された摩擦杭とを有し、摩擦杭は、その引抜き耐力によって水平土圧に抗する安定モーメントを擁壁に与えるので、水平土圧に対する鋼管杭の負荷を軽減することができる。また、鋼管杭及び摩擦杭の杭芯間隔(E)は、各杭の杭径の平均値((D1+D2)/2)の2.5倍以上の寸法に設定すれば良く、従って、鋼管杭と大きく離間することなく摩擦杭を鋼管杭の背後に配置し得るので、摩擦杭の杭頭部が固定される地中梁の突出寸法(K)と壁体の高さ寸法(H)との寸法比(K/H)を2/5以下の値に設定し、高地盤の掘削範囲を比較的狭い範囲に制限することができる。 According to the above configuration of the present invention, the retaining wall has a steel pipe pile that supports its own weight (vertical load) of the wall body and a friction pile arranged behind the steel pipe pile, and the friction pile has a pull-out strength thereof. Since the retaining wall is given a stable moment against the horizontal earth pressure, the load on the steel pipe pile against the horizontal earth pressure can be reduced. In addition, the pile core spacing (E) of the steel pipe pile and the friction pile may be set to a dimension that is 2.5 times or more the average value ((D1 + D2) / 2) of the pile diameter of each pile. Since the friction pile can be placed behind the steel pipe pile without a large separation, the dimension between the protrusion dimension (K) of the underground beam to which the pile head of the friction pile is fixed and the height dimension (H) of the wall body. The ratio (K / H) can be set to a value of 2/5 or less, and the excavation range of high ground can be limited to a relatively narrow range.

本発明の擁壁及びその施工方法によれば、摩擦杭によって擁壁の安定モーメントを確保し得るので、大形基礎フーチングの施工を省略し、施工の容易性、工期の短縮、掘削土量の削減、コンクリート量及び鉄筋量の削減、工事費の低廉化等を図ることができる。しかも、本発明の擁壁及びその施工方法によれば、地中梁を施工可能な範囲まで高地盤を掘削すれば良く、バットレス又は錘形基礎等を高地盤に設置せず、高地盤掘削工事の前に矢板及び綱管杭を高地盤に埋入することもなく擁壁を施工することができる。また、地中梁は、壁体の下端部に隣接して配置されるので、高地盤に建設すべき建築物又は構造物の配置又は構造等が地中梁の存在によって設計上の制限又は制約を受けるという問題は生じない。 According to the retaining wall of the present invention and its construction method, a stable moment of the retaining wall can be secured by the friction pile, so that the construction of the large foundation footing is omitted, the construction is easy, the construction period is shortened, and the amount of excavated soil is reduced. It is possible to reduce the amount of concrete and reinforcing bars, and reduce the construction cost. Moreover, according to the retaining wall of the present invention and its construction method, it is sufficient to excavate the high ground to the extent that the underground beam can be constructed, and the high ground excavation work is performed without installing a batless or a pyramid foundation on the high ground. Retaining walls can be constructed without embedding sheet piles and rope piles in the high ground in front of. In addition, since the underground beam is arranged adjacent to the lower end of the wall body, the arrangement or structure of the building or structure to be constructed on the high ground is restricted or restricted in design due to the existence of the underground beam. There is no problem of receiving.

本発明の好ましい実施形態において、高地盤及び低地盤の平均的高低差は、3m以下であり、高地盤の平均的掘削範囲は、壁体の壁厚方向又は該壁体の壁芯と直交する方向において、掘削前の低地盤の境界から1m以上且つ2m以下の範囲に制限される。 In a preferred embodiment of the present invention, the average height difference between the high ground and the low ground is 3 m or less, and the average excavation range of the high ground is orthogonal to the wall thickness direction of the wall body or the wall core of the wall body. In the direction, it is limited to a range of 1 m or more and 2 m or less from the boundary of the low ground before excavation.

また、本発明の好適な実施形態によれば、上記擁壁は、壁芯方向に離間した地中梁同士を一体的に相互連結する鉄筋コンクリート構造の補剛底盤を更に有し、補剛底盤は、上記壁体の下端部から高地盤側に一体的に延出又は突出しており、壁体、地中梁及び補剛底板の下端面又は下側面は水平に連続し、捨てコンクリート面等の水平な施工面に接地可能な水平底面を構成する。好ましくは、地中梁に対する摩擦杭の杭頭部の埋込み長さ(h7)は、摩擦杭の杭径(D2)の1.0倍〜2.0倍の範囲内の寸法に設定され、地中梁の突出寸法(K)と壁体の高さ寸法(H)との寸法比(K/H)は、2/5以下の値に設定され、鋼管杭及び摩擦杭の杭芯間隔(E)は、各杭の杭径の平均値(D1+D2)/2)の2.5倍以上且つ3.5倍以下の寸法に設定される。所望により、地中梁の矩形断面の縦横比(h5/W2)は、1.0〜2.0の範囲内の値に設定される。 Further, according to a preferred embodiment of the present invention, the retaining wall further has a stiffening bottom plate having a reinforced concrete structure for integrally interconnecting underground beams separated in the wall core direction, and the stiffening bottom plate , The lower end of the wall body extends or protrudes integrally to the high ground side, and the lower end surface or lower side surface of the wall body, underground beam and stiffening bottom plate is horizontally continuous, and the discarded concrete surface, etc. is horizontal. A horizontal bottom surface that can be grounded on a concrete construction surface is constructed. Preferably, the embedding length (h7) of the pile head of the friction pile with respect to the underground beam is set to a dimension within the range of 1.0 to 2.0 times the pile diameter (D2) of the friction pile, and the ground. dimensional ratio between the height dimension of the projecting dimension of the center sill (K) and the wall (H) (K / H) is 2/5 is set to the following values, pile core spacing steel Kankui and friction piles (E) is set to a size of 2.5 times or more and 3.5 times or less of the average value (D1 + D2) / 2) of the pile diameter of each pile. If desired, the aspect ratio (h5 / W2) of the rectangular cross section of the underground beam is set to a value in the range of 1.0 to 2.0.

好ましくは、上記鋼管杭は、所定の耐力を有する地盤の支持層によって鉛直に支持される先端支持杭であり、上記摩擦杭は、地盤に鉛直に圧入し又は打撃力により地盤に鉛直に打込んだ均一な真円形断面の開端鋼管杭、或いは、予め地盤に施工された鉛直な杭孔内に鉛直に挿入し且つセメントミルクによって地盤に拘束した均一な真円形断面の開端鋼管杭からなる。本発明の好適な実施形態において、摩擦杭は、地盤に鉛直に圧入される開端鋼管杭であり、摩擦杭の外周面及び内周面は地盤に摩擦接触し、摩擦杭の引抜き抵抗は、地盤に対する外周面摩擦力及び内周面摩擦力によって得られる。 Preferably, the steel pipe pile is a tip support pile that is vertically supported by a support layer of the ground having a predetermined yield strength, and the friction pile is vertically press-fitted into the ground or driven vertically into the ground by a striking force. It consists of an open-ended steel pipe pile having a uniform perfect circular cross section, or an open-ended steel pipe pile having a uniform perfect circular cross section that is vertically inserted into a vertical pile hole previously constructed in the ground and restrained in the ground by cement milk. In a preferred embodiment of the present invention, the friction pile is an open-ended steel pipe pile that is vertically press-fitted into the ground, the outer peripheral surface and the inner peripheral surface of the friction pile are in frictional contact with the ground, and the pull-out resistance of the friction pile is the ground. It is obtained by the frictional force on the outer peripheral surface and the frictional force on the inner peripheral surface.

本発明の擁壁及びその施工方法によれば、大形基礎フーチングの施工を省略し、施工の容易性、工期の短縮、掘削土量の削減、コンクリート量及び鉄筋量の削減、工事費の低廉化等を図り、しかも、バットレス又は錘形基礎等を高地盤に設置せず、高地盤掘削工事の前に矢板及び綱管杭を高地盤に埋入することもなく擁壁を施工することができ、加えて、水平土圧に対する鋼管杭の負荷を軽減することができる。 According to the retaining wall of the present invention and the construction method thereof, the construction of the large foundation footing is omitted, the construction is easy, the construction period is shortened, the amount of excavated earth is reduced, the amount of concrete and the amount of reinforcing bars is reduced, and the construction cost is low. In addition, it is possible to construct a retaining wall without installing sheet piles and rope pipe piles in the high ground before the high ground excavation work without installing batless or pyramidal foundations on the high ground. In addition, the load on the steel pipe pile with respect to the horizontal earth pressure can be reduced.

図1(A)は、本発明に係る擁壁の構造を示す縦断面図であり、図1(B)は、図1(A)のI−I線における断面図である。FIG. 1 (A) is a vertical sectional view showing the structure of the retaining wall according to the present invention, and FIG. 1 (B) is a sectional view taken along line I-I of FIG. 1 (A). 図2は、本発明に係る擁壁の構造を示す横断面図である。FIG. 2 is a cross-sectional view showing the structure of the retaining wall according to the present invention. 図3(A)は、擁壁を施工するために高地盤の被掘削部分を掘削した状態を示す地盤の縦断面図であり、図3(B)及び図3(C)は、図3(A)のII−II線及びIII−III線における断面図である。FIG. 3A is a vertical cross-sectional view of the ground showing a state in which an excavated portion of the high ground is excavated to construct a retaining wall, and FIGS. 3B and 3C are 3 (C). It is sectional drawing in A) II-II line and III-III line. 図4は、配筋・型枠工程の工程を示す擁壁の縦断面図である。FIG. 4 is a vertical cross-sectional view of the retaining wall showing the steps of the bar arrangement / formwork process. 図5(A)は、コンクリート打設工程を示す擁壁の縦断面図であり、図5(B)は、図5(A)のIV−IV線における断面図である。5 (A) is a vertical sectional view of a retaining wall showing a concrete placing process, and FIG. 5 (B) is a sectional view taken along line IV-IV of FIG. 5 (A).

以下、添付図面を参照して本発明の好適な実施形態について詳細に説明する。 Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

図1(A)及び図2は、本発明に係る擁壁の構造を示す縦断面図及び横断面図であり、図1(B)は、図1(A)のI−I線における断面図である。各図において、壁体の壁芯方向がX方向として示され、壁芯と直交する方向がY方向として示されている。 1 (A) and 2 are a vertical sectional view and a horizontal sectional view showing the structure of the retaining wall according to the present invention, and FIG. 1 (B) is a sectional view taken along line I-I of FIG. 1 (A). Is. In each figure, the wall core direction of the wall body is shown as the X direction, and the direction orthogonal to the wall core is shown as the Y direction.

擁壁1は、低地盤LG側への高地盤HGの崩壊又は崩落を阻止するように高地盤HGの地形に相応して配置される。擁壁1は、X方向(壁芯方向)に所定間隔を隔てて整列配置された鋼管杭2と、鋼管杭2の高地盤側において鋼管杭2からY方向に杭芯間隔Eを隔ててX方向に整列配置された鋼管杭3と、鋼管杭2の杭列に沿ってX方向に延在する鉄筋コンクリート構造の壁体4と、壁体4の下端部から高地盤側且つY方向に一体的に延出する鉄筋コンクリート構造の地中梁5と、壁体4の背面からY方向に一体的に延出し且つ隣り合う地中梁5同士を一体的に相互連結する鉄筋コンクリート構造の補剛底盤部6とから構成され、高地盤HGの土圧に耐える一体的な土留め壁を構成する。地中梁5は、壁体2の鋼管杭埋設部分と、鋼管杭3の杭頭部埋設部分とを繋ぐ矩形断面の水平部材であり、壁体2に作用する転倒モーメントを引抜き力として杭3の杭頭部3aに伝達する引抜き力伝達部分を構成する。 The retaining wall 1 is arranged corresponding to the topography of the high ground HG so as to prevent the collapse or collapse of the high ground HG toward the low ground LG side. The retaining wall 1 is arranged with steel pipe piles 2 arranged in the X direction (wall core direction) at predetermined intervals, and X with a pile core spacing E in the Y direction from the steel pipe piles 2 on the high ground side of the steel pipe piles 2. The steel pipe piles 3 arranged in the direction, the wall body 4 having a reinforced concrete structure extending in the X direction along the pile row of the steel pipe pile 2, and the wall body 4 integrated from the lower end to the high ground side and in the Y direction. Reinforced concrete structure underground beam 5 extending to and the stiffening bottom 6 of the reinforced concrete structure integrally extending from the back surface of the wall body 4 in the Y direction and integrally interconnecting adjacent underground beams 5 It is composed of and, and constitutes an integrated retaining wall that can withstand the earth pressure of high ground HG. The underground beam 5 is a horizontal member having a rectangular cross section that connects the steel pipe pile buried portion of the wall body 2 and the pile head buried portion of the steel pipe pile 3, and the pile 3 uses the overturning moment acting on the wall body 2 as a pulling force. It constitutes a pull-out force transmission portion to be transmitted to the pile head 3a of the pile head 3a.

本例の擁壁1は、低地盤面La及び高地盤面Haの高低差が3m以下の地形に好ましく適用される。本例において、低地盤面La及び高地盤面Haの高低差は、2m〜3m、例えば、約2.5mであり、低地盤面Laから壁体4の天端面4aまでの距離、即ち、天端面4aの高さh1は、実質的に地盤の高低差と等しく、約2.5mである。壁体4、地中梁5及び補剛底盤部6の下端面又は下側面は、水平に連続する擁壁1の水平底面を構成する。擁壁1の水平底面は、採石7a及び捨てコンクリート7bによって整地又は整備された水平な施工面7に接地する。なお、必ずしも擁壁1の底面を単一の水平面として設計しなくとも良く、所望により、段差又は高低差を擁壁1の底面に形成しても良い。 The retaining wall 1 of this example is preferably applied to a terrain in which the height difference between the low ground surface La and the high ground surface Ha is 3 m or less. In this example, the height difference between the low ground surface La and the high ground surface Ha is 2 m to 3 m, for example, about 2.5 m, and the distance from the low ground surface La to the top surface 4a of the wall body 4, that is, the top surface. The height h1 of 4a is substantially equal to the height difference of the ground, and is about 2.5 m. The lower end surface or lower side surface of the wall body 4, the underground beam 5, and the stiffening bottom plate portion 6 constitutes the horizontal bottom surface of the horizontally continuous retaining wall 1. The horizontal bottom surface of the retaining wall 1 is grounded on a horizontal construction surface 7 that has been leveled or maintained by quarrying 7a and waste concrete 7b. The bottom surface of the retaining wall 1 does not necessarily have to be designed as a single horizontal plane, and a step or height difference may be formed on the bottom surface of the retaining wall 1 if desired.

鋼管杭2、3は夫々、均一な真円形断面の開端鋼管杭からなり、地盤に鉛直に埋入される。鋼管杭2は、先端支持杭であり、鋼管杭2の先端部2bは、好ましくは、N値10以上の支持層Sに達する。鋼管杭2の支持力は、先端支持力及び杭周面摩擦力の双方によって得られる。施工面7を基準とした鋼管杭2の杭長(埋込み長)L1は、支持層Sの深さに相応して相違するが、本例では、支持層Sの深さを約6mと仮定し、杭長L1を約6mと仮定する。 The steel pipe piles 2 and 3 each consist of open-ended steel pipe piles having a uniform perfect circular cross section, and are vertically embedded in the ground. The steel pipe pile 2 is a tip support pile, and the tip 2b of the steel pipe pile 2 preferably reaches a support layer S having an N value of 10 or more. The bearing capacity of the steel pipe pile 2 is obtained by both the tip bearing capacity and the frictional force on the peripheral surface of the pile. The pile length (embedded length) L1 of the steel pipe pile 2 based on the construction surface 7 differs according to the depth of the support layer S, but in this example, the depth of the support layer S is assumed to be about 6 m. , It is assumed that the pile length L1 is about 6 m.

他方、施工面7を基準とした鋼管杭3の杭長(埋込み長)L2は、本例において、約3mに設定される。鋼管杭3の先端部3bは、支持層Sに達しておらず、従って、鋼管杭3は、実質的に杭周面摩擦力のみによって支持力を得る形式の杭、即ち、摩擦杭である。鋼管杭2、3の杭芯2c、3cが図1(A)に示され、鋼管杭2、3の杭列中心2d、3dが、図2に示されている。杭列中心2dは、壁体4の壁芯4dと一致する。 On the other hand, the pile length (embedding length) L2 of the steel pipe pile 3 with respect to the construction surface 7 is set to about 3 m in this example. The tip portion 3b of the steel pipe pile 3 does not reach the support layer S. Therefore, the steel pipe pile 3 is a pile of a type in which the bearing force is obtained substantially only by the frictional force on the peripheral surface of the pile, that is, a friction pile. The pile cores 2c and 3c of the steel pipe piles 2 and 3 are shown in FIG. 1 (A), and the pile row centers 2d and 3d of the steel pipe piles 2 and 3 are shown in FIG. The pile row center 2d coincides with the wall core 4d of the wall body 4.

本例において、鋼管杭2は、直径D1=約320mmの鋼管(肉厚約7mm)からなり、鋼管杭3は、直径D2=約270mmの鋼管(肉厚約6mm)からなる。鋼管杭2の杭頭部2aの高さh2は、約2mに設定され、低地盤面Laと施工面7との高低差h3は、約400mmに設定され、壁体4内に鉛直に埋入する鋼管杭2の埋込み寸法は、約2.4m(h2+h3)に設定される。鋼管杭2の壁体埋込部分は、擁壁1の鋼製支柱又は立柱を構成する。他方、鋼管杭3の杭頭部3aは、高さh7の埋込み寸法だけ地中梁5に鉛直に埋入する。構造計画又は構造設計において地中梁5と杭頭部3aとの接合部を杭頭固定の支持構造と見做すには、杭頭部3aの埋込み寸法(高さh7)を直径D2(杭径)以上の寸法に設定する必要があるので、高さh7は、本例において、約300mmに設定される。 In this example, the steel pipe pile 2 is composed of a steel pipe (wall thickness of about 7 mm) having a diameter of D1 = about 320 mm, and the steel pipe pile 3 is made of a steel pipe (wall thickness of about 6 mm) having a diameter of D2 = about 270 mm. The height h2 of the pile head 2a of the steel pipe pile 2 is set to about 2 m, the height difference h3 between the low ground surface La and the construction surface 7 is set to about 400 mm, and it is vertically embedded in the wall body 4. The embedded size of the steel pipe pile 2 is set to about 2.4 m (h2 + h3). The wall-embedded portion of the steel pipe pile 2 constitutes a steel column or a vertical column of the retaining wall 1. On the other hand, the pile head 3a of the steel pipe pile 3 is vertically embedded in the underground beam 5 by the embedding dimension of the height h7. In order to regard the joint between the underground beam 5 and the pile head 3a as a support structure for fixing the pile head in the structural plan or structural design, the embedded dimension (height h7) of the pile head 3a is set to the diameter D2 (pile). Since it is necessary to set the size to be larger than the diameter), the height h7 is set to about 300 mm in this example.

図2に示す如く、鋼管杭2、3は、壁体4と直交する方向(Y方向)において杭芯間隔Eを隔てて整列配置される。杭芯間隔Eは、少なくとも2.5×(D1+D2)/2の寸法に設定する必要があるので、本例において、杭芯間隔Eは、約750mmに設定される。 As shown in FIG. 2, the steel pipe piles 2 and 3 are aligned and arranged with the pile core spacing E in the direction orthogonal to the wall body 4 (Y direction). Since the pile core spacing E needs to be set to a dimension of at least 2.5 × (D1 + D2) / 2, the pile core spacing E is set to about 750 mm in this example.

本例において、この他の擁壁1の各部寸法は、以下のとおり設定される。
壁体4の壁厚W1:約500mm
鋼管杭2、3の杭芯間隔F(X方向):約2m
地中梁5の幅W2:約450mm
地中梁5の高さh5:約550mm
地中梁5及び補剛底盤部6の突出寸法K:約750mm
補剛底盤部6の厚さ(高さ)h6:約250mm
In this example, the dimensions of each part of the other retaining wall 1 are set as follows.
Wall thickness of wall 4 W1: Approximately 500 mm
Pile core spacing F (X direction) of steel pipe piles 2 and 3: Approximately 2 m
Width of underground beam 5 W2: Approximately 450 mm
Height of underground beam 5 h5: Approximately 550 mm
Projection size K of underground beam 5 and stiffening bottom plate 6: Approximately 750 mm
Thickness (height) of stiffening bottom plate 6 h6: Approximately 250 mm

地中梁5の突出寸法Kと壁体4の高さH(=h1+h3)との寸法比K/Hは、好ましくは、2/5以下、更に好ましくは、1/3以下に設定される。本例において、寸法比K/Hは、約1/4に設定される。なお、本例では、地中梁5及び底盤部6は、同一の突出寸法Kを有するが、地中梁5及び底盤部6の各突出寸法を異なる寸法値に設定することも可能である。また、地中梁5の矩形断面の縦横比(h5/W2)は、1.0以上2.0以下の範囲内の値に好ましく設定し得る。更に、地中梁5の高さh5は、補剛底盤部6の厚さh6の1.5倍以上(好ましくは2.0倍以上)且つ3.0倍以下の値に好ましく設定し得る。なお、本例においては、擁壁1は、縦横比(h5/W2)が1.0以上の矩形断面の引抜き力伝達部分として地中梁5を備えるが、地中梁5は、1.0未満の縦横比(h5/W2)を有する矩形断面(又は基礎スラブ形態)に設計することも可能である。 The dimensional ratio K / H of the protruding dimension K of the underground beam 5 and the height H (= h1 + h3) of the wall body 4 is preferably set to 2/5 or less, more preferably 1/3 or less. In this example, the dimensional ratio K / H is set to about 1/4. In this example, the underground beam 5 and the bottom plate portion 6 have the same protrusion dimension K, but the protrusion dimensions of the underground beam 5 and the bottom plate portion 6 can be set to different dimensional values. Further, the aspect ratio (h5 / W2) of the rectangular cross section of the underground beam 5 can be preferably set to a value within the range of 1.0 or more and 2.0 or less. Further, the height h5 of the underground beam 5 can be preferably set to a value of 1.5 times or more (preferably 2.0 times or more) and 3.0 times or less of the thickness h6 of the stiffening bottom plate portion 6. In this example, the retaining wall 1 includes an underground beam 5 as a pulling force transmitting portion having a rectangular cross section having an aspect ratio (h5 / W2) of 1.0 or more, but the underground beam 5 is 1.0. It is also possible to design a rectangular cross section (or basic slab form) with an aspect ratio of less than (h5 / W2).

擁壁1の自重(鉛直荷重)は、鋼管杭2の先端支持力とによって実質的に支持される。なお、壁体4、地中梁5及び補剛盤6が接地する接地地盤(施工面7)の支持力や、鋼管杭2の杭周面摩擦力に起因する鋼管杭2の支持力も擁壁1に作用するが、これらの支持力は先端支持力に比べて相対的に小さく、本例においては、構造計画上、考慮しないものとする。 The own weight (vertical load) of the retaining wall 1 is substantially supported by the tip bearing capacity of the steel pipe pile 2. The bearing wall of the grounding ground (construction surface 7) on which the wall body 4, the underground beam 5 and the stiffener 6 touch the ground, and the bearing capacity of the steel pipe pile 2 due to the frictional force on the pile peripheral surface of the steel pipe pile 2 are also retained. Although it acts on 1, these bearing capacitys are relatively small compared to the tip bearing capacity, and in this example, they are not considered in the structural plan.

擁壁1に作用する土圧、地震力等の水平荷重は、主として、鋼管杭3の引抜き耐力に起因する擁壁1の安定モーメントと、杭2、3に対する水平地盤反力とによって支持される。鋼管杭3の引抜き耐力は、実質的に鋼管杭3の杭周面摩擦力によって得られる。なお、壁体4、地中梁5及び底盤部6と地盤との間に作用する摩擦力や、地中梁5及び補剛盤6の自重に起因する擁壁1の安定モーメントも働くが、この摩擦力及び安定モーメントは、引抜き耐力及び水平地盤反力に比べて相対的に小さく、本例においては、構造計画上、考慮しないものとする。 The horizontal load such as earth pressure and seismic force acting on the retaining wall 1 is mainly supported by the stabilizing moment of the retaining wall 1 due to the pull-out strength of the steel pipe pile 3 and the horizontal ground reaction force against the piles 2 and 3. .. The pull-out strength of the steel pipe pile 3 is substantially obtained by the pile peripheral friction force of the steel pipe pile 3. The frictional force acting between the wall body 4, the underground beam 5 and the bottom 6 and the ground, and the stabilizing moment of the retaining wall 1 due to the weight of the underground beam 5 and the stiffener 6 also act. This frictional force and stable moment are relatively small compared to the pull-out strength and the horizontal ground reaction force, and are not considered in the structural plan in this example.

従って、擁壁1は、実質的に鋼管杭2の鉛直支持力によって自重(鉛直荷重)を支持し、鋼管杭3の引抜き耐力と、杭2、3に対する水平地盤反力とによって水平荷重を実質的に支持する構造を有する擁壁として把握し得る。このような擁壁構造によれば、安定モーメント確保のための大形基礎フーチングの施工や、バットレス又は錘形基礎等の設置は、必要とされない。また、鋼管杭3の引抜き耐力により得られる安定モーメントは、水平土圧に対する鋼管杭の負荷を軽減する。更に、以下に説明する如く、擁壁1は、地盤掘削工事の前に矢板及び綱管杭を高地盤に埋入する施工を要しない。 Therefore, the retaining wall 1 substantially supports its own weight (vertical load) by the vertical bearing capacity of the steel pipe pile 2, and the horizontal load is substantially supported by the pull-out strength of the steel pipe pile 3 and the horizontal ground reaction force against the piles 2 and 3. It can be grasped as a retaining wall having a structure that supports the plumb bob. According to such a retaining wall structure, construction of a large foundation footing for securing a stable moment and installation of a buttress or a pyramid foundation are not required. Further, the stable moment obtained by the pull-out strength of the steel pipe pile 3 reduces the load on the steel pipe pile with respect to the horizontal earth pressure. Further, as described below, the retaining wall 1 does not require the work of embedding the sheet pile and the rope pipe pile in the high ground before the ground excavation work.

次に、擁壁1の施工方法について説明する。 Next, the construction method of the retaining wall 1 will be described.

図3(A)は、擁壁1を施工するために高地盤HGの被掘削部分NGを掘削した状態を示す地盤の縦断面図であり、図3(B)及び図3(C)は、図3(A)のII−II線及びIII−III線における断面図である。図4は、配筋・型枠工程の工程を示す擁壁の縦断面図であり、図5(A)は、コンクリート打設工程を示す擁壁の縦断面図であり、図5(B)は、図5(A)のIV−IV線における断面図である。 FIG. 3 (A) is a vertical cross-sectional view of the ground showing a state in which the excavated portion NG of the high ground HG is excavated in order to construct the retaining wall 1, and FIGS. 3 (B) and 3 (C) are views. 3 is a cross-sectional view taken along the line II-II and Line III-III of FIG. 3 (A). FIG. 4 is a vertical cross-sectional view of the retaining wall showing the steps of the bar arrangement / formwork process, and FIG. 5 (A) is a vertical cross-sectional view of the retaining wall showing the concrete placing process, FIG. 5 (B). Is a cross-sectional view taken along the line IV-IV of FIG. 5 (A).

図3には、掘削前の法面(比較的急勾配の傾斜面)IGが破線で示されるとともに、擁壁1を施工すべき水平地盤面8と、概ね鉛直な掘削壁面9とを掘削工事によって露出せしめた状態が示されている。掘削範囲は、鋼管杭2、3及び擁壁1を施工可能な最小限の範囲に限定され、平面視においてY方向に概ね1.5〜2m程度の範囲内の領域である。即ち、擁壁1の施工においては、大形フーチングの施工や、バットレス又は錘形基礎等の設置のために高地盤HGを大きく掘削することを要さず、地盤掘削工事の前に矢板及び綱管杭を高地盤に埋入する工程も要しない。 In FIG. 3, the slope (relatively steep slope) IG before excavation is shown by a broken line, and the horizontal ground surface 8 on which the retaining wall 1 should be constructed and the generally vertical excavation wall surface 9 are excavated. The exposed state is shown by. The excavation range is limited to the minimum range in which the steel pipe piles 2, 3 and the retaining wall 1 can be constructed, and is a region within a range of about 1.5 to 2 m in the Y direction in a plan view. That is, in the construction of the retaining wall 1, it is not necessary to excavate a large ground HG for the construction of a large footing or the installation of a buttress or a pyramid foundation, and the sheet pile and rope are used before the ground excavation work. There is no need for the process of embedding pipe piles in the high ground.

鋼管杭2の施工において、鉛直な杭孔Qがアースオーガー(図示せず)によって支持層Sまで掘削され、一般に根固め液として使用されるセメントミルクMがオーガー先端から杭孔Q内に吐出される。後続の杭建込み工程において、鋼管杭2が杭孔Q内に鉛直に挿入され、セメントミルクMが鋼管杭2の先端開口から鋼管杭2の内部に流入する。セメントミルクMが概ね水平地盤面8のレベルGLまで鋼管杭2の外周部及び内部に充填された状態が図3(A)に示されている。セメントミルクMの上側の管内領域は、頂部開口形の開放空間2gである。所定時間経過後にセメントミルクMが硬化し、所期の強度を発現すると、鋼管杭2の先端部2bは、セメントミルクMの固化体によって支持層Sに拘束されるとともに、鋼管杭2の先端支持力が得られる。鋼管杭2の外周部のセメントミルク固化体は、鋼管杭2を地盤Jに拘束し、鋼管杭2の内部のセメントミルク固化体は、鋼管杭2の強度及び剛性を向上させる。 In the construction of the steel pipe pile 2, a vertical pile hole Q is excavated to the support layer S by an earth auger (not shown), and cement milk M, which is generally used as a rooting liquid, is discharged from the tip of the auger into the pile hole Q. To. In the subsequent pile building step, the steel pipe pile 2 is vertically inserted into the pile hole Q, and the cement milk M flows into the inside of the steel pipe pile 2 from the tip opening of the steel pipe pile 2. FIG. 3A shows a state in which the cement milk M is filled in the outer peripheral portion and the inner portion of the steel pipe pile 2 up to the level GL of the horizontal ground surface 8. The upper pipe area of the cement milk M is a top-opening open space of 2 g. When the cement milk M hardens after a lapse of a predetermined time and develops the desired strength, the tip portion 2b of the steel pipe pile 2 is restrained by the solidified body of the cement milk M to the support layer S and supports the tip of the steel pipe pile 2. Power is gained. The cement milk solidified body on the outer periphery of the steel pipe pile 2 restrains the steel pipe pile 2 to the ground J, and the cement milk solidified body inside the steel pipe pile 2 improves the strength and rigidity of the steel pipe pile 2.

鋼管杭3の施工において、鋼管杭3は、オーガ併用の杭打ち機等によって地盤に圧入される。図3(C)に示す如く、鋼管杭3の外周面及び内周面の双方が地盤Jに摩擦接触し、外周面摩擦力及び内周面摩擦力が得られ、従って、鋼管杭3は十分な引抜き耐力を発揮する。地盤Jの上側の管内領域は、頂部開口形の開放空間3gである。所望により、鋼管杭2の施工方法と同様の施工方法によって鋼管杭3を施工しても良い。この場合、鋼管杭2は、セメントミルク固化体を介して地盤Jと一体化し、これにより、引抜き耐力を発揮する。 In the construction of the steel pipe pile 3, the steel pipe pile 3 is press-fitted into the ground by a pile driver or the like combined with an auger. As shown in FIG. 3C, both the outer peripheral surface and the inner peripheral surface of the steel pipe pile 3 are in frictional contact with the ground J, and the outer peripheral surface friction force and the inner peripheral surface friction force are obtained. Therefore, the steel pipe pile 3 is sufficient. Demonstrates excellent pull-out resistance. The area inside the pipe above the ground J is an open space of 3 g with an open top. If desired, the steel pipe pile 3 may be constructed by the same construction method as that of the steel pipe pile 2. In this case, the steel pipe pile 2 is integrated with the ground J via the cement milk solidified body, whereby the pull-out strength is exhibited.

鋼管杭2、3の施工が完了すると、図4に示す如く、水平地盤面8上に採石7a及び捨てコンクリート7bが敷設又は打設され、捨てコンクリート7bの上面によって水平な施工面7が形成される。次いで、コンクリート打設用の型枠10が施工面7上に建込まれるとともに、擁壁1の鉄筋(図示せず)が施工される。高地盤側の型枠10の建込み作業を行うための作業空間αが鋼管杭2と掘削壁面9との間に形成されているので、作業者等は、比較的容易に配筋・型枠工事を実施することができる。壁体4の壁筋として、D10〜D25程度の汎用の異形鉄筋が使用され、壁筋間隔は、100mm〜300mm程度の寸法に設定される。また、地中梁5の梁主筋として、D16〜D29程度の汎用の異形鉄筋が使用され、地中梁5のスタラップ筋として、D13〜D19程度の汎用の異形鉄筋が使用される。更に、補剛底盤部6の配筋として、D10〜D25程度の汎用の異形鉄筋が使用され、配筋間隔は、100mm〜300mm程度の寸法に設定される。 When the construction of the steel pipe piles 2 and 3 is completed, as shown in FIG. 4, quarrying 7a and waste concrete 7b are laid or placed on the horizontal ground surface 8, and the horizontal construction surface 7 is formed by the upper surface of the waste concrete 7b. To. Next, the formwork 10 for placing concrete is erected on the construction surface 7, and the reinforcing bars (not shown) of the retaining wall 1 are constructed. Since the work space α for building the formwork 10 on the high ground side is formed between the steel pipe pile 2 and the excavation wall surface 9, workers and the like can relatively easily arrange the reinforcement and formwork. Construction can be carried out. As the wall bar of the wall body 4, general-purpose deformed reinforcing bars of about D10 to D25 are used, and the wall bar spacing is set to a dimension of about 100 mm to 300 mm. Further, general-purpose deformed reinforcing bars of about D16 to D29 are used as the beam main bars of the underground beam 5, and general-purpose deformed reinforcing bars of about D13 to D19 are used as the stirrup bars of the underground beam 5. Further, general-purpose deformed reinforcing bars of about D10 to D25 are used as the reinforcing bars of the stiffening bottom plate portion 6, and the reinforcing bar spacing is set to a dimension of about 100 mm to 300 mm.

配筋・型枠の施工が完了すると、図5(A)に示す如く、生コンクリートRCを型枠10内に流し込むコンクリート打設工程が実施される。生コンクートRCは、型枠10内のコンクリート打設空間に充填されるとともに、図5(B)に示す如く、鋼管杭2、3の上端開口を介して鋼管杭2、3内に流入し、鋼管杭2、3の上部開放空間2g、3g(図3(A))に充填される。所定のコンクリート養生期間の経過後に型枠10内の生コンクリートRCが硬化し、所要の強度を発現した後、型枠10の解体・撤去が実施され、しかる後、埋め戻し土によって作業空間αが埋め戻され、かくして、図1及び図2に示す擁壁1の施工が完了する。 When the construction of the reinforcement arrangement and the formwork is completed, as shown in FIG. 5 (A), the concrete placing process of pouring the ready-mixed concrete RC into the formwork 10 is carried out. The ready-mixed concrete RC fills the concrete casting space in the formwork 10 and flows into the steel pipe piles 2 and 3 through the upper end openings of the steel pipe piles 2 and 3 as shown in FIG. 5 (B). The upper open spaces 2g and 3g (FIG. 3A) of the steel pipe piles 2 and 3 are filled. After the ready-mixed concrete RC in the formwork 10 has hardened after the elapse of the predetermined concrete curing period and the required strength is exhibited, the formwork 10 is dismantled and removed, and then the backfill soil creates a work space α. It is backfilled and thus the construction of the retaining wall 1 shown in FIGS. 1 and 2 is completed.

以上、本発明の好適な実施形態について詳細に説明したが、本発明は上記実施形態に限定されるものではなく、特許請求の範囲に記載された本発明の範囲内で種々の変形又は変更が可能であることはいうまでもない。 Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited to the above embodiments, and various modifications or modifications can be made within the scope of the present invention described in the claims. It goes without saying that it is possible.

例えば、上記摩擦杭は、所望の引抜き抵抗が得られる限りにおいて、埋込み工法、打撃工法又は回転杭工法等の他の工法によって施工される鋼管杭であっても良い。 For example, the friction pile may be a steel pipe pile constructed by another construction method such as an embedding method, a striking method or a rotary pile method as long as a desired pull-out resistance can be obtained.

また、上記実施形態は、直線的な壁体を有する擁壁に関するのものであるが、湾曲した平面形態の擁壁、或いは、角度をなして複雑に屈曲する擁壁等の各種平面形態の擁壁に対して本発明を適用しても良い。 Further, although the above embodiment relates to a retaining wall having a linear wall body, a retaining wall having a curved plane shape or a retaining wall having a complicatedly bent shape at an angle or the like is supported. The present invention may be applied to a wall.

更に、壁体の支柱又は立柱を構成する低地盤側の鋼管杭と、摩擦杭を構成する高地盤側の鋼管杭との杭芯間隔(E)は、杭毎に相違しても良く、また、低地盤側及び高地盤側の各杭の本数は必ずしも同数でなくとも良く、必ずしも壁厚方向又は壁体直交方向(Y方向)に整列しなくとも良い。 Further, the pile core spacing (E) between the steel pipe piles on the low ground side forming the pillars or vertical pillars of the wall body and the steel pipe piles on the high ground side forming the friction piles may be different for each pile. The number of piles on the low ground side and the high ground side does not necessarily have to be the same, and the piles do not necessarily have to be aligned in the wall thickness direction or the wall body orthogonal direction (Y direction).

また、上記実施形態では、円形断面の鋼管杭を使用しているが、方形、多角形、楕円形、長円形等の断面の鋼管を鋼管杭として使用しても良い。 Further, in the above embodiment, a steel pipe pile having a circular cross section is used, but a steel pipe having a cross section such as a square, a polygon, an ellipse, or an oval may be used as the steel pipe pile.

本発明は、崖、急傾斜地又は水路等に施工される擁壁に適用される。本発明は殊に、高さ3m以下の擁壁に好ましく適用し得る。本発明の擁壁は、大型フーチングの施工を要しないので、擁壁の施工性等は、大きく改善する。また、本発明によれば、高地盤の掘削量を削減し得るとともに、バットレス又は錘形基礎等を高地盤に設置せず、高地盤掘削工事の前に矢板及び綱管杭を高地盤に埋入することもなく擁壁を施工することができ、しかも、水平土圧に対する鋼管杭の負荷を軽減し得るので、従来の擁壁構造では擁壁の施工が困難であった地盤においても擁壁を施工することができ、従って、その実用的効果は顕著である。 The present invention applies to retaining walls constructed on cliffs, steep slopes, waterways, and the like. The present invention can be particularly preferably applied to a retaining wall having a height of 3 m or less. Since the retaining wall of the present invention does not require the construction of a large footing, the workability of the retaining wall and the like are greatly improved. Further, according to the present invention, the amount of excavation in the high ground can be reduced, and the sheet pile and the rope pipe pile are buried in the high ground before the high ground excavation work without installing the batless or the pyramid foundation in the high ground. Since the retaining wall can be constructed without entering, and the load of the steel pipe pile against the horizontal earth pressure can be reduced, the retaining wall can be constructed even on the ground where it was difficult to construct the retaining wall with the conventional retaining wall structure. Can be constructed, and therefore its practical effect is remarkable.

1 擁壁
2 鋼管杭(先端支持杭)
3 鋼管杭(摩擦杭)
2a:3a 杭頭部
2b:3b 先端部
4 壁体
5 地中梁(引抜き力伝達部分)
6 補剛底盤部
7 水平施工面
8 水平地盤面
9 掘削壁面
S 支持層
HG 高地盤
LG 低地盤
1 Retaining wall 2 Steel pipe pile (tip support pile)
3 Steel pipe pile (friction pile)
2a: 3a Pile head 2b: 3b Tip 4 Wall 5 Underground beam (pulling force transmission part)
6 Stiffening bottom 7 Horizontal construction surface 8 Horizontal ground surface 9 Excavation wall surface S Support layer HG High ground LG Low ground

Claims (8)

土留め壁を構成する鉄筋コンクリート構造の壁体と、上端部を前記壁体に埋込まれ、該壁体の自重を支持する鋼管杭とを有する擁壁において、
前記壁体の壁厚方向又は該壁体の壁芯と直交する方向に前記鋼管杭から間隔を隔てて前記壁体の高地盤側に配置され、水平土圧に抗する安定モーメントをその引抜き耐力によって擁壁に与える摩擦杭と、
前記壁体の下端部から高地盤側に一体的に延出又は突出し、該壁体に作用する転倒モーメントを前記摩擦杭の杭頭部に伝達する鉄筋コンクリート構造の地中梁とを有し、
該地中梁は、鉄筋をコンクリート内に配筋してなる梁主筋及びスタラップ筋を有し、前記摩擦杭の杭頭部は、前記地中梁に埋入し、該地中梁に固定されていることを特徴とする擁壁。
In a retaining wall having a wall body having a reinforced concrete structure constituting an earth retaining wall and a steel pipe pile having an upper end embedded in the wall body and supporting the weight of the wall body.
It is arranged on the high ground side of the wall body at a distance from the steel pipe pile in the wall thickness direction of the wall body or in the direction orthogonal to the wall core of the wall body, and its pull-out strength withstands a stable moment against horizontal earth pressure. The friction stakes given to the retaining wall by
The integrally to extend or protrude from the lower end of the wall to a high ground side, and a ground beam of reinforced concrete structure for transmitting the overturning moment acting on the wall body pile head of the friction piles,
該地center sill is Rebar has a beam main reinforcements and Sturup muscle formed by Haisuji in the concrete, pile head of the friction piles, and embedded in the ground beam, is fixed to the ground beam Retaining wall characterized by being.
壁芯方向に離間した前記地中梁と一体化して該地中梁を相互連結する鉄筋コンクリート構造の補剛底盤を有し、該補剛底盤は、前記壁体の下端部から高地盤側に一体的に延出又は突出していることを特徴とする請求項1に記載の擁壁。 Has a stiffening bottom plate of reinforced concrete structures interconnecting the ground beam integral with the underground beams spaced Kabeshin direction,該補Tsuyoshisokoban is integrally from the lower end of the wall to a high ground-side The retaining wall according to claim 1, characterized in that it extends or protrudes from the ground. 前記壁体、地中梁及び補剛底板の下端面又は下側面は水平に連続し、水平な施工面に接地可能な水平底面を構成することを特徴とする請求項に記載の擁壁。 The retaining wall according to claim 2 , wherein the lower end surface or the lower side surface of the wall body, the underground beam and the stiffening bottom plate is horizontally continuous, and constitutes a horizontal bottom surface that can be grounded to the horizontal construction surface. 前記鋼管杭は、所定の耐力を有する地盤の支持層によって鉛直に支持される先端支持杭であり、前記摩擦杭は、地盤に鉛直に圧入し又は打撃力により地盤に鉛直に打込んだ均一な真円形断面の開端鋼管杭、或いは、予め地盤に施工された鉛直な杭孔内に鉛直に挿入し且つセメントミルクによって地盤に拘束した均一な真円形断面の開端鋼管杭からなることを特徴とする請求項1乃至3のいずれか1項に記載の擁壁。 The steel pipe pile is a tip support pile that is vertically supported by a support layer of the ground having a predetermined yield strength, and the friction pile is a uniform pressure pile that is vertically press-fitted into the ground or vertically driven into the ground by a striking force. It is characterized by consisting of an open-ended steel pipe pile having a perfect circular cross section, or an open-ended steel pipe pile having a uniform perfect circular cross section that is vertically inserted into a vertical pile hole previously constructed in the ground and restrained to the ground by cement milk. The retaining wall according to any one of claims 1 to 3. 前記地中梁に対する前記摩擦杭の杭頭部の埋込み長さ(h7)は、該摩擦杭の杭径(D2)の1.0倍〜2.0倍の範囲内の寸法に設定され、前記地中梁の突出寸法(K)と前記壁体の高さ寸法(H)との寸法比(K/H)は、2/5以下の値に設定され、前記鋼管杭及び摩擦杭の杭芯間隔(E)は、各杭の杭径の平均値((D1+D2)/2)の2.5倍以上且つ3.5倍以下の寸法に設定されていることを特徴とする請求項1乃至4のいずれか1項に記載の擁壁。 The embedded length (h7) of the pile head of the friction pile with respect to the underground beam is set to a dimension within the range of 1.0 to 2.0 times the pile diameter (D2) of the friction pile. The dimensional ratio (K / H) between the protruding dimension (K) of the underground beam and the height dimension (H) of the wall body is set to a value of 2/5 or less, and the pile core of the steel pipe pile and the friction pile. Claims 1 to 4 are characterized in that the interval (E) is set to a dimension of 2.5 times or more and 3.5 times or less of the average value ((D1 + D2) / 2) of the pile diameter of each pile. The retaining wall described in any one of the items. 前記摩擦杭の外周面及び内周面は地盤に摩擦接触せしめ、該摩擦杭の引抜き抵抗を地盤に対する外周面摩擦力及び内周面摩擦力によって得られるようにしたことを特徴とする請求項1乃至5のいずれか1項に記載の擁壁。 The outer peripheral surface and the inner peripheral surface of the friction pile are brought into frictional contact with the ground, and the pull-out resistance of the friction pile is obtained by the outer peripheral surface friction force and the inner peripheral surface friction force with respect to the ground. The retaining wall according to any one of 5 to 5. 請求項1乃至6のいずれか1項に記載された擁壁の施工方法であって、
高地盤を掘削し、前記壁体及び地中梁を施工可能な水平地盤面を形成する掘削・整地工程と、
前記鋼管杭及び摩擦杭を前記水平地盤面に施工し、該鋼管杭及び摩擦杭の上部を前記水平地盤面から上方に突出させる杭打ち工程と、
前記壁体及び地中梁の配筋・型枠工程と、
前記壁体及び地中梁のコンクリート打設工程と、
前記壁体と高地盤面との間に形成された作業空間に埋め戻し土を埋め戻す埋め戻し工程とを有することを特徴とする擁壁の施工方法。
The method for constructing a retaining wall according to any one of claims 1 to 6.
Excavation and grading process to excavate high ground and form a horizontal ground surface on which the wall body and underground beam can be constructed,
A pile driving step of constructing the steel pipe pile and the friction pile on the horizontal ground surface and projecting the upper part of the steel pipe pile and the friction pile upward from the horizontal ground surface.
Reinforcement / formwork process of the wall body and underground beam,
The concrete placing process of the wall body and the underground beam, and
A method for constructing a retaining wall, which comprises a backfilling step of backfilling backfilling soil in a work space formed between the wall body and a highland surface.
高地盤及び低地盤の平均的高低差は、3m以下であり、高地盤の平均的掘削範囲は、前記壁体の壁厚方向又は該壁体の壁芯と直交する方向において、掘削前の低地盤の境界から1m以上且つ2m以下の範囲に制限されることを特徴とする請求項7に記載の施工方法。 The average height difference between the high ground and the low ground is 3 m or less, and the average excavation range of the high ground is low before excavation in the wall thickness direction of the wall body or in the direction orthogonal to the wall core of the wall body. The construction method according to claim 7, wherein the construction method is limited to a range of 1 m or more and 2 m or less from the boundary of the ground.
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