JP2010133206A - Structure and construction method for newly-built structure using existing pile - Google Patents

Structure and construction method for newly-built structure using existing pile Download PDF

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JP2010133206A
JP2010133206A JP2008312716A JP2008312716A JP2010133206A JP 2010133206 A JP2010133206 A JP 2010133206A JP 2008312716 A JP2008312716 A JP 2008312716A JP 2008312716 A JP2008312716 A JP 2008312716A JP 2010133206 A JP2010133206 A JP 2010133206A
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existing
ground
pile
existing pile
new
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JP5181290B2 (en
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Akira Ishikawa
明 石川
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Shimizu Construction Co Ltd
Shimizu Corp
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Shimizu Construction Co Ltd
Shimizu Corp
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Abstract

<P>PROBLEM TO BE SOLVED: To construct a newly-built structure as a spread foundation structure on ground where an existing pile remains. <P>SOLUTION: An existing structure, which is supported by the existing pile 12 buried in the ground G, is removed except for the existing pile 12. The upper end of the existing pile 12 is cut off by performing the pit excavation of the ground G on the periphery of the upper end of the existing pile 12. Subsequently, the newly-built structure 10 is constructed on the composite ground G1 which is formed by making a backfill material 2 arranged in a pit-excavated part. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

本発明は、地盤中に残存する既存杭を利用する新設構造物の構造および構築方法に関する。   The present invention relates to a structure and a construction method for a new structure using an existing pile remaining in the ground.

従来、杭に支持された既存構造物を解体して新設構造物を建設する場合に、既存構造物の既存杭を撤去して新設杭を施工し、新設杭を杭基礎とした新設構造物を構築する方法や、既存杭を地盤中に残存させたまま新設杭を施工し、新設杭のみを杭基礎とした新設構造物を構築する方法が行われている。
しかし、既存杭を撤去して新設杭を施工する方法では、既存杭の撤去にかかるコストや労力が大きく、特に、既存杭が場所打ちコンクリート杭の場合には撤去に莫大なコストや労力がかかる。また、既存杭周辺の地盤は既存杭が引き抜かれた後に緩んでしまうことがあった。また、既存杭を地盤中に残存させたまま新設杭を施工する方法では、新設杭の設置位置に制約があるため、新設杭の施工が困難であったり、新設構造物の設計に制約が出ることがあった。
Conventionally, when dismantling an existing structure supported by a pile and constructing a new structure, the existing pile is removed from the existing structure, and the new pile is constructed. The construction method and the method of constructing a new structure with the existing pile remaining in the ground and constructing the new structure using only the new pile as the foundation of the pile are performed.
However, with the method of removing existing piles and constructing new piles, the cost and labor required to remove existing piles are large, especially when existing piles are cast-in-place concrete piles, the removal requires enormous costs and labor. . Also, the ground around the existing piles sometimes loosened after the existing piles were pulled out. In addition, in the method of constructing a new pile with the existing pile remaining in the ground, the installation position of the new pile is restricted, so the construction of the new pile is difficult or the design of the new structure is restricted There was a thing.

そこで、地盤中に既存杭を残存させて、この既存杭を杭基礎として再利用し、耐力が不足する場合には新設杭も施工して、これらの杭で支持される新設構造物を構築する方法が行われている。
特許文献1によれば、既存構造物を支持する既存杭を残して既存構造物を撤去し、既存杭の上に厚い鉄筋コンクリートスラブなどのマット基礎を設けて、マット基礎の上に新設構造物を構築する方法が提案されている。特許文献1による方法では、新設構造物の鉛直荷重を既存杭およびマット基礎によって十分に支持できると共に、既存杭を再利用することにより、既存杭の撤去や埋め戻しが不要になり、新設杭の施工は必要に応じて行えばよいので、新設構造物の構築にかかるコストや労力を軽減させることができる。
また、特許文献2によれば、既存杭を避けて新設杭を打設し、既存杭と新設杭との上にマット基礎を設けて、マット基礎の上に新設建物を構築する方法が提案されている。支持地盤に達している既存杭はマット基礎とは定着させずに、マット基礎から受ける鉛直力を主に負担し、新設杭はマット基礎と剛接合により一体化させて、マット基礎から受ける地震水平力を負担しているので、新設杭は水平力に抵抗できる長さであればよく、必ずしも支持地盤に達している必要はない。特許文献2による方法では、既存杭を再利用できて、新設杭の施工も軽減できるので、新設構造物の構築にかかるコストや労力を軽減させることができる。
特開2002−146809号公報 特開2003−96794号公報
Therefore, existing piles are left in the ground, and the existing piles are reused as pile foundations. When the proof strength is insufficient, new piles are also constructed, and new structures supported by these piles are constructed. The way is done.
According to Patent Document 1, an existing structure is removed while leaving an existing pile supporting an existing structure, a mat foundation such as a thick reinforced concrete slab is provided on the existing pile, and a new structure is provided on the mat foundation. A method of construction has been proposed. In the method according to Patent Document 1, the vertical load of the new structure can be sufficiently supported by the existing pile and the mat foundation, and by reusing the existing pile, it becomes unnecessary to remove and backfill the existing pile. Since construction may be performed as necessary, the cost and labor required for constructing a new structure can be reduced.
According to Patent Document 2, a method is proposed in which a new pile is placed avoiding an existing pile, a mat foundation is provided on the existing pile and the new pile, and a new building is constructed on the mat foundation. ing. Existing piles that have reached the supporting ground do not settle with the mat foundation, but mainly bear the vertical force received from the mat foundation, and the new pile is integrated with the mat foundation by rigid joints, and the earthquake horizontal that is received from the mat foundation. Since the force is borne, the new pile need only have a length that can resist horizontal force and does not necessarily have to reach the supporting ground. In the method according to Patent Document 2, since existing piles can be reused and construction of new piles can be reduced, costs and labor required for constructing a new structure can be reduced.
JP 2002-146809 A JP 2003-96794 A

しかしながら、特許文献1および2による既存杭を杭基礎として再利用し、新設構造物を構築する方法では以下のような問題があった。
既存構造物が存在している状態では、実際の既存杭の状況や設置位置が図面と一致しているかを確認することができない。そして、既存構造物の撤去後に、例えば、既存杭の劣化などによって既存杭が杭基礎として耐力が不十分であることや、既存杭の設置位置が図面と異なることなどが判明すると、新設構造物自体の設計変更を行わなければならないこともあり、新設構造物の設計や工期、コストなどに変更が生じてしまうという問題があった。
However, the existing piles according to Patent Documents 1 and 2 are reused as pile foundations, and the method for constructing a new structure has the following problems.
In the state where the existing structure exists, it is impossible to confirm whether the actual situation and the installation position of the existing pile coincide with the drawing. After the existing structure is removed, for example, if the existing pile is insufficiently proof as a pile foundation due to deterioration of the existing pile, or the installation position of the existing pile is different from the drawing, the new structure There is a problem that the design of the new structure must be changed, and the design, construction period, and cost of the new structure are changed.

本発明は、上述する問題点に鑑みてなされたもので、新設構造物は既存杭を杭基礎として利用する構造物ではなく、直接基礎構造物として既存杭の残存する地盤の上に構築することができる既存杭を利用した新設構造物の構造および構築方法を提供することを目的とする。   The present invention has been made in view of the above-mentioned problems, and the newly constructed structure is not a structure that uses an existing pile as a pile foundation, but is constructed directly on the ground where the existing pile remains as a foundation structure. The purpose is to provide a structure and construction method for new structures using existing piles.

上記目的を達成するため、本発明に係る既存杭を利用した新設構造物の構造は、既存構造物を支持する既存杭を残して既存構造物を撤去し、既存杭の残存する地盤の上に構築される新設構造物の構造であって、既存杭の上端部の周辺の地盤が壺掘りされて既存杭の上端部が切除され、埋め戻し材が配設された地盤の上部に新設構造物が構築されることを特徴とする。
また、本発明に係る既存杭を利用した新設構造物の構築方法では、既存構造物を支持する既存杭を残して既存構造物を撤去し、既存杭の上端部の周辺の地盤を壺掘りして既存杭の上端部を切除し、埋め戻し材を配設した地盤の上に新設構造物を構築することを特徴とする。
本発明では、既存杭の上端部の周辺の地盤を壺掘りして既存杭の上端部を切除し、埋め戻し材を配設した地盤に新設構造物が構築されることにより、新設構造物は既存杭を杭基礎とする構造物でなく、直接基礎構造物として既存杭の残存した地盤に構築することができる。
また、既存杭は上端部のみ撤去し、再利用するので既存杭の撤去にかかるコストや労力を低減させることができる。
In order to achieve the above object, the structure of the new structure using the existing pile according to the present invention is to remove the existing structure, leaving the existing pile supporting the existing structure, on the remaining ground of the existing pile. The structure of a new structure to be constructed, where the ground around the upper end of the existing pile is dug and the upper end of the existing pile is excised, and the new structure is placed above the ground where the backfill material is arranged Is constructed.
Moreover, in the construction method of the new structure using the existing pile according to the present invention, the existing structure is removed while leaving the existing pile supporting the existing structure, and the ground around the upper end of the existing pile is dug. Then, the upper end of the existing pile is cut off, and a new structure is constructed on the ground where the backfill material is arranged.
In the present invention, the new structure is constructed by digging the ground around the upper end of the existing pile, excising the upper end of the existing pile, and constructing the new structure on the ground where the backfill material is disposed. It can be built on the ground where existing piles remain as a direct foundation structure rather than a structure based on existing piles.
Moreover, since the existing pile removes only an upper end part and reuses, the cost and labor concerning removal of an existing pile can be reduced.

また、本発明に係る既存杭を利用した新設構造物の構造では、埋め戻し材は壺掘りされた地盤の周辺の地盤よりも剛性の低い材料であることが好ましい。
本発明では、埋め戻し材を壺掘りされた地盤の周辺の地盤よりも剛性の低い材料とすることにより、既存杭から新設構造物の基礎スラブに作用する応力の集中を緩和させて、新設構造物の沈下量を均等にさせることができる。
Moreover, in the structure of a new structure using the existing pile according to the present invention, it is preferable that the backfill material is a material having lower rigidity than the ground around the ground dug.
In the present invention, the backfill material is made of a material having lower rigidity than the ground around the ground excavated, thereby reducing the concentration of stress acting on the foundation slab of the new structure from the existing pile, and the new structure The amount of sinking of objects can be made uniform.

また、本発明に係る既存杭を利用した新設構造物の構造では、既存杭が残存する地盤に新設の杭または地盤改良体が配設される構成としてもよい。
本発明では、既存杭が残存する地盤に新設の杭または地盤改良体を配設することにより、地盤の支持力が足りない場合にも地盤の補強ができて、新設構造物の沈下量を均等にさせることができる。新設の杭または地盤改良体は、地盤の既存杭の残存する領域に既存杭に混ざって配設されてもよく、また、地盤の既存杭の残存する領域を外れた新設構造物の下に配設されてもよく、地盤の既存杭の残存する領域および領域外の新設構造物の下に配設してもよい。
Moreover, in the structure of the new structure using the existing pile which concerns on this invention, it is good also as a structure by which a new pile or a ground improvement body is arrange | positioned in the ground where the existing pile remains.
In the present invention, by installing a new pile or ground improvement body on the ground where the existing pile remains, the ground can be reinforced even when the ground support is insufficient, and the amount of settlement of the new structure is evenly distributed. Can be made. The new pile or ground improvement body may be placed in the existing area of the existing pile on the ground and mixed with the existing pile, and the existing area of the existing pile on the ground is placed under the new structure. It may be installed, and may be arranged under the existing structure pile of the ground and under the new structure outside the area.

本発明によれば、既存杭の上端部の周辺の地盤を壺掘りして既存杭の上端部を切除し、埋め戻し材を配設した地盤に新設構造物が構築されるので、新設構造物は既存杭を杭基礎として利用せず、新設構造物を既存杭の残存した地盤の上に直接基礎構造物として構築することができる。   According to the present invention, since the ground around the upper end of the existing pile is dug and the upper end of the existing pile is excised, and the new structure is built on the ground where the backfill material is arranged, the new structure Does not use the existing pile as a pile foundation, but can construct a new structure directly on the remaining ground of the existing pile as a foundation structure.

以下、本発明の第一の実施の形態による既存杭を利用した新設構造物の構造について、図1乃至図4に基づいて説明する。
図1は既存杭に支持された既存構造物の一例を示す図、図2は既存杭の切除を説明する図、図3は既存杭の切除した部分の埋め戻しを説明する図、図4は本発明の第一の実施の形態による既存杭を利用した新設構造物の一例を示す図である。
Hereinafter, the structure of the new structure using the existing pile according to the first embodiment of the present invention will be described with reference to FIGS. 1 to 4.
FIG. 1 is a diagram illustrating an example of an existing structure supported by an existing pile, FIG. 2 is a diagram illustrating excision of the existing pile, FIG. 3 is a diagram illustrating backfilling of the excised portion of the existing pile, and FIG. It is a figure which shows an example of the new structure using the existing pile by 1st embodiment of this invention.

第一の実施の形態による既存杭を利用した新設構造物の構造は、図1に示すような、地盤Gに埋設された既存杭12に支持された既存構造物11が既存杭12を残して撤去され、図2に示すように、既存杭12の上端部12aの周辺の地盤Gが壺掘りされて既存杭12の上端部12aが切除され、図3に示すように、壺掘りされた地盤Gに埋め戻し材2が配設されて形成された複合地盤G1上に、図4に示すように、新設構造物10が構築される構成である。   The structure of the new structure using the existing pile according to the first embodiment is that the existing structure 11 supported by the existing pile 12 embedded in the ground G as shown in FIG. As shown in FIG. 2, the ground G around the upper end 12a of the existing pile 12 is excavated and the upper end 12a of the existing pile 12 is excised as shown in FIG. As shown in FIG. 4, the new structure 10 is constructed on the composite ground G <b> 1 formed by arranging the backfill material 2 on G.

既存構造物11は、鉄筋コンクリートなどの構造物で、例えば柱状の地盤改良体や現場打ちコンクリート杭などの既存杭12に支持されている。
切除される既存杭12の上端部12aの長さLは、既存杭12の杭径Dの1〜3倍ほどの長さとする。
埋め戻し材2は、壺掘りされた地盤Gの周辺の地盤Gよりも剛性が低い材料とし、例えば砂、粘土、原位置発生土、流動化処理土などを採用する。
The existing structure 11 is a structure such as reinforced concrete, and is supported by an existing pile 12 such as a columnar ground improvement body or a cast-in-place concrete pile.
The length L of the upper end portion 12 a of the existing pile 12 to be cut is set to a length of about 1 to 3 times the pile diameter D of the existing pile 12.
The backfill material 2 is made of a material having lower rigidity than the ground G around the ground G excavated, and for example, sand, clay, in-situ generated soil, fluidized soil, and the like are adopted.

新設構造物10は、例えば鉄筋コンクリートなどの構造物で、既存杭12を杭基礎としない直接基礎構造物である。新設構造物10と既存杭12とは、間に埋め戻し材2が配設されて連結しない構造である。新設構造物10を設計する際には、新設構造物10が構築される複合地盤G1の支持力や沈下量を算定し、支持力の不足や、新設構造物10の沈下量にばらつきが生じないかの検討を行う。   The new structure 10 is a structure such as reinforced concrete and is a direct foundation structure that does not use the existing pile 12 as a pile foundation. The new structure 10 and the existing pile 12 are structures in which the backfilling material 2 is disposed between them and is not connected. When the new structure 10 is designed, the bearing capacity and sinking amount of the composite ground G1 on which the new structure 10 is built are calculated, and there is no variation in the bearing capacity deficiency and the sinking amount of the new structure 10. Do a review.

複合地盤G1の沈下量の予測算定に関しては、例えば以下のような等価剛性評価法を用いて容易に算出することができる。
既存杭12の配設されている複合地盤G1を、既存杭12とその周囲の原地盤とからなる所定面積の単位周期構造体の集合体とし、単位周期構造体は剛性の異なる原地盤と既存杭12との複合体で、複合体全体の剛性を等価とみなせる剛性(以下、これを等価剛性という)を有する単一の均質体とみなす。また、単位周期構造体の面積に対する既存杭12の面積の比を改良率とする。
Regarding the predicted calculation of the subsidence amount of the composite ground G1, it can be easily calculated using, for example, the following equivalent stiffness evaluation method.
The composite ground G1 in which the existing piles 12 are arranged is an aggregate of unit periodic structures having a predetermined area made up of the existing piles 12 and the surrounding raw ground. The composite with the pile 12 is regarded as a single homogeneous body having rigidity that can be regarded as equivalent to the rigidity of the entire composite (hereinafter referred to as equivalent rigidity). Moreover, let the ratio of the area of the existing pile 12 with respect to the area of a unit periodic structure be an improvement rate.

そして、この等価剛性と改良率との関係を単位周期構造体の縦横比、既存杭12の剛性、原地盤の剛性をパラメータとして簡易チャート化し、これに基づいて改良率とこれに対応する等価剛性とを求め、その等価剛性と既存杭12の配設された複合地盤G1全体に作用する外力に基づいて複合地盤G1の等価剛性を算定する。沈下量の算定は上記等価剛性を用いて、有限要素解析もしくは梁バネモデルにより求めればよい。   Then, the relationship between the equivalent stiffness and the improvement rate is simplified with the aspect ratio of the unit periodic structure, the stiffness of the existing pile 12 and the stiffness of the original ground as parameters, and based on this, the improvement rate and the equivalent stiffness corresponding thereto And the equivalent rigidity of the composite ground G1 is calculated based on the equivalent rigidity and the external force acting on the entire composite ground G1 in which the existing piles 12 are disposed. The amount of settlement can be calculated by finite element analysis or a beam spring model using the equivalent rigidity.

次に、上述した第一の実施の形態による既存杭を利用した新設構造物の構築方法について図面を用いて説明する。
図1に示す既存構造物11を既存杭12を残して撤去し、図2に示すように既存杭12の上端部12aの周辺の地盤Gを壺掘りし、上端部12aをはつって切除する。そして、図4に示すように、壺掘りされた地盤Gに埋め戻し材2を配設して複合地盤G1を形成する。そしてこの複合地盤G1の上に新設構造物10を構築する。
Next, the construction method of the new structure using the existing pile according to the first embodiment described above will be described with reference to the drawings.
The existing structure 11 shown in FIG. 1 is removed leaving the existing pile 12, and the ground G around the upper end portion 12a of the existing pile 12 is dug as shown in FIG. 2, and the upper end portion 12a is cut off. . And as shown in FIG. 4, the backfill material 2 is arrange | positioned in the ground G excavated, and the composite ground G1 is formed. And the new structure 10 is constructed | assembled on this composite ground G1.

上述した第一の実施の形態による既存杭を利用した新設構造物の構築方法では、既存杭12の上端部12aの周辺の地盤Gを壺掘りして上端部12aを切除し、この部分に埋め戻し材2を配設した複合地盤G1に新設構造物10を構築しているので、新設構造物10は既存杭12を杭基礎とした構造物ではなく、複合地盤G1上に構築される直接基礎構造物として設計できる。そして、既存杭12に関する調査や申請を軽減若しくは省くことができる。
また、既存杭12は上端部12aのみを切除し他は再利用するので、既存杭12の撤去にかかる労力やコストを軽減することができる。
In the construction method of the new structure using the existing pile according to the first embodiment described above, the ground G around the upper end portion 12a of the existing pile 12 is dug and the upper end portion 12a is excised and buried in this portion. Since the new structure 10 is constructed on the composite ground G1 in which the return material 2 is disposed, the new structure 10 is not a structure based on the existing pile 12 but a direct foundation constructed on the composite ground G1. Can be designed as a structure. And the investigation and application regarding the existing pile 12 can be reduced or omitted.
Moreover, since the existing pile 12 cuts only the upper end part 12a and reuses others, the labor and cost concerning removal of the existing pile 12 can be reduced.

また、埋め戻し材2は切除された既存杭12の上端部12aの周辺の地盤Gよりも剛性の低い材料とするので、既存杭12から埋め戻し材2を介して新設構造物10の基礎スラブに作用する応力集中を緩和し、新設構造物10の沈下量を均一にすることができる。
また、複合地盤G1の沈下量の予測算定を等価剛性評価法に基づいて行うので、沈下量を容易に算定できて、複合地盤G1を均質な地盤とみなして新設構造物10を設計することができる。
Moreover, since the backfilling material 2 is made of a material having lower rigidity than the ground G around the upper end portion 12a of the existing pile 12 that has been cut off, the foundation slab of the new structure 10 from the existing pile 12 via the backfilling material 2 is used. It is possible to alleviate the stress concentration acting on the, and make the amount of settlement of the new structure 10 uniform.
Moreover, since the prediction calculation of the subsidence amount of the composite ground G1 is performed based on the equivalent stiffness evaluation method, the subsidence amount can be easily calculated, and the new structure 10 can be designed by regarding the composite ground G1 as a homogeneous ground. it can.

次に、第二の実施の形態について、添付図面に基づいて説明するが、上述の第一の実施の形態と同一又は同様な部材、部分には同一の符号を用いて説明を省略し、第一の実施の形態と異なる構成について説明する。
図5は、本発明の第二の実施の形態による既存杭を利用した新設構造物の一例を示す図である。
Next, the second embodiment will be described with reference to the accompanying drawings, but the same or similar members and parts as those in the first embodiment described above are denoted by the same reference numerals, and the description thereof is omitted. A configuration different from that of the embodiment will be described.
FIG. 5 is a diagram showing an example of a new structure using an existing pile according to the second embodiment of the present invention.

第二の実施の形態による既存杭を利用した新設構造物の構造は、第一の実施の形態による既存杭を利用した新設構造物の構造において、地盤を補強する新設杭を配設した構成である。
図5に示すように、新設構造物20は、例えば鉄筋コンクリートなどの構造物で、既存杭12の残存する領域より広い範囲の地盤Gに接地して構築される。第一の実施の形態と同様に、新設構造物20が構築される地盤Gの支持力や沈下量が算定されて、地盤Gの支持力が不足している部分や、沈下量にばらつきが生じる部分に新設杭3を配設して複合地盤G2を形成する。
The structure of the new structure using the existing pile according to the second embodiment is the structure of the new structure using the existing pile according to the first embodiment in which a new pile that reinforces the ground is arranged. is there.
As shown in FIG. 5, the new structure 20 is a structure such as reinforced concrete, for example, and is constructed by grounding the ground G in a wider range than the area where the existing pile 12 remains. Similar to the first embodiment, the supporting force and the amount of settlement of the ground G on which the new structure 20 is constructed are calculated, and the portion where the supporting force of the ground G is insufficient and the amount of settlement are varied. The composite pile G2 is formed by arranging the new pile 3 in the portion.

新設杭3は、例えば現場打ちコンクリート杭や柱状の地盤改良体などで、地盤の補強材として配設される。新設杭3は、新設構造物20とは接続されず、新設杭3の配設する場所や形状、また数量は地盤Gの強度によって適宜設定される。そして、第二の実施の形態による既存杭を利用した新設構造物の構造では、新設杭3は地盤Gの既存杭12が残存する領域に既存杭12に混ざって配設されると共に、地盤Gの既存杭12の残存する領域を外れた新設構造物20の下にも配設される。   The new pile 3 is, for example, an on-site concrete pile or a columnar ground improvement body, and is disposed as a ground reinforcing material. The new pile 3 is not connected to the new structure 20, and the location, shape, and quantity of the new pile 3 are appropriately set according to the strength of the ground G. And in the structure of the new structure using the existing pile by 2nd embodiment, while the new pile 3 is mixed with the existing pile 12 in the area | region where the existing pile 12 of the ground G remains, ground G The existing pile 12 is disposed under the new structure 20 outside the remaining region.

第二の実施の形態による既存杭を利用した新設構造物の構造では、地盤G中に補強材として新設杭3を配設することにより、地盤Gの支持力の不足や沈下量にばらつきが生じることを防止できて、均質な複合地盤G2を形成できるので、第一の実施の形態と同様に、新設構造物20は既存杭12を杭基礎とした構造物ではなく、複合地盤G2上に構築される直接基礎構造物として設計できる。   In the structure of the new structure using the existing pile according to the second embodiment, the new pile 3 is disposed as a reinforcing material in the ground G, so that the supporting force of the ground G is insufficient and the amount of subsidence varies. Since this can prevent the formation of a homogeneous composite ground G2, as in the first embodiment, the new structure 20 is not a structure based on the existing pile 12 but a structure on the composite ground G2. Can be designed as a direct substructure.

ここで、既存杭の残存する地盤に建設された新設構造物の基礎スラブおよび階ごとの沈下量の測定を行った。
図6は既存杭の残存する地盤と新設構造物とを示す平面図および断面図、図7は、図6に示すA−A,B−B、C−C測線における新設構造物の基礎スラブおよび階ごとの沈下量を示す図である。
Here, the foundation slab of the new structure constructed on the ground where the existing piles remained and the amount of settlement for each floor were measured.
FIG. 6 is a plan view and a cross-sectional view showing the remaining ground of the existing pile and the new structure, and FIG. 7 is a basic slab of the new structure along the AA, BB, and CC survey lines shown in FIG. It is a figure which shows the amount of subsidence for every floor.

図6に示すように、新設構造物30は、既存杭12の残存する複合地盤G1と既存杭12の埋設されていない原地盤G3との上にわたって構築されており、上述した本発明の第一の実施の形態による既存杭を利用した新設構造物の構造の5階建ての直接基礎構造物である。
既存杭12は、図示しない既存構造物を支持していた場所打ちコンクリート杭で、杭径Dは1.0mである。切除される既存杭12の上端部12a長さLは1.0mで、既存杭12の上端部12aが切除された部分には埋め戻し材2が配設されている。
新設構造物30を構築するにあたり、複合地盤G1及び原地盤G3の沈下量および支持力を算定し、新設の杭や地盤改良体の打ち増しは必要ないと判断した。
As shown in FIG. 6, the new structure 30 is constructed over the composite ground G1 in which the existing pile 12 remains and the original ground G3 in which the existing pile 12 is not embedded, and the first structure of the present invention described above. It is a 5-story direct foundation structure of the structure of a new structure using the existing pile according to the embodiment.
The existing pile 12 is a cast-in-place concrete pile supporting an existing structure (not shown), and the pile diameter D is 1.0 m. The length L of the upper end 12a of the existing pile 12 to be cut is 1.0 m, and the backfilling material 2 is disposed in the portion where the upper end 12a of the existing pile 12 is cut.
In constructing the new structure 30, the amount of subsidence and bearing capacity of the composite ground G1 and the original ground G3 were calculated, and it was determined that it was not necessary to add new piles or ground improvement bodies.

図7に示すように、新設構造物30の沈下量は、既存杭12の残存する複合地盤G1と既存杭12が埋設されていない原地盤G3とでは大きな差はなく、全体に亘って沈下量のばらつきが少ないことがわかる。   As shown in FIG. 7, the subsidence amount of the new structure 30 is not significantly different between the composite ground G1 where the existing pile 12 remains and the original ground G3 where the existing pile 12 is not buried, and the subsidence amount over the whole. It can be seen that there is little variation in.

以上、本発明による既存杭を利用した新設構造物の構造および構築方法の実施の形態について説明したが、本発明は上記の実施の形態に限定されるものではなく、その趣旨を逸脱しない範囲で適宜変更可能である。
また、上記の第二の実施の形態では、地盤Gの既存杭12が残存する領域の内外に新設杭3を配設して、この地盤Gに新設構造物20を構築しているが、地盤Gの既存杭12が残存する領域内に新設杭3を配設して、この領域内に新設構造物を構築してもよく、また、新設杭3を配設せずに地盤Gの既存杭12が残存する領域の内外にわたって新設構造物を構築してもよい。
要は、本発明において所期の機能が得られればよいのである。
As mentioned above, although the structure of the new structure using the existing pile by this invention and embodiment of the construction method were demonstrated, this invention is not limited to said embodiment, In the range which does not deviate from the meaning It can be changed as appropriate.
Moreover, in said 2nd embodiment, although the new pile 3 is arrange | positioned inside and outside the area | region where the existing pile 12 of the ground G remains, the new structure 20 is constructed | assembled in this ground G, The new pile 3 may be arranged in the region where the existing pile 12 of the G remains, and a new structure may be constructed in this region, or the existing pile of the ground G without the new pile 3 being arranged. A new structure may be constructed over the inside and outside of the region where 12 remains.
In short, it is only necessary to obtain the desired function in the present invention.

既存杭に支持された既存構造物の一例を示す図である。It is a figure which shows an example of the existing structure supported by the existing pile. 既存杭の切除を示す図である。It is a figure which shows excision of the existing pile. 既存杭の切除した部分の埋め戻しを示す図である。It is a figure which shows the backfill of the part which the existing pile was excised. 本発明の第一の実施の形態による既存杭を利用した新設構造物の一例を示す図である。It is a figure which shows an example of the new structure using the existing pile by 1st embodiment of this invention. 本発明の第二の実施の形態による既存杭を利用した新設構造物の一例を示す図である。It is a figure which shows an example of the new structure using the existing pile by 2nd embodiment of this invention. 既存杭の残存する地盤と新設構造物とを示す平面図および断面図である。It is the top view and sectional drawing which show the ground with which the existing pile remains, and a new structure. 図6に示すA−A,B−B、C−C測線における新設構造物の基礎スラブおよび階ごとの沈下量を示す図である。It is a figure which shows the amount of subsidence for every foundation slab and floor of a new structure in the AA, BB, CC line shown in FIG.

符号の説明Explanation of symbols

2 埋め戻し材
3 新設杭
10 新設構造物
11 既存構造物
12 既存杭
G 地盤
2 Backfill 3 New pile 10 New structure 11 Existing structure 12 Existing pile G Ground

Claims (4)

既存構造物を支持する既存杭を残して前記既存構造物を撤去し、前記既存杭の残存する地盤の上に構築される新設構造物の構造であって、
前記既存杭の上端部の周辺の地盤が壺掘りされて前記既存杭の上端部が切除され、埋め戻し材が配設された地盤の上部に前記新設構造物が構築されることを特徴とする既存杭を利用した新設構造物の構造。
The existing structure is removed by leaving the existing pile supporting the existing structure, and is constructed on the ground where the existing pile remains,
The ground around the upper end of the existing pile is dug up, the upper end of the existing pile is excised, and the new structure is constructed on the upper part of the ground where the backfill material is disposed. Structure of a new structure using existing piles.
前記埋め戻し材は壺掘りされた前記地盤の周辺の地盤よりも剛性の低い材料であることを特徴とする請求項1に記載の既存杭を利用した新設構造物の構造。   The structure of a new structure using an existing pile according to claim 1, wherein the backfill material is a material having lower rigidity than the ground around the ground that has been dug. 前記既存杭が残存する地盤に新設の杭または地盤改良体が配設されることを特徴とする請求項1または2に記載の既存杭を利用した新設構造物の構造。   The structure of the new structure using the existing pile according to claim 1 or 2, wherein a new pile or a ground improvement body is disposed on the ground where the existing pile remains. 既存構造物を支持する既存杭を残して前記既存構造物を撤去し、前記既存杭の上端部の周辺の地盤を壺掘りして前記既存杭の上端部を切除し、埋め戻し材を配設した地盤の上に新設構造物を構築することを特徴とする既存杭を利用した新設構造物の構築方法。   The existing pile is removed leaving the existing pile supporting the existing structure, the ground around the upper end of the existing pile is dug, the upper end of the existing pile is excised, and backfilling material is disposed The construction method of the new structure using the existing pile characterized by constructing the new structure on the ground.
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JP2012246656A (en) * 2011-05-26 2012-12-13 Takenaka Komuten Co Ltd Foundation structure of building and method for constructing foundation of building
JP2014201948A (en) * 2013-04-04 2014-10-27 株式会社竹中工務店 Building design method
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JP2017179751A (en) * 2016-03-28 2017-10-05 旭化成ホームズ株式会社 Foundation structure and building
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JP2002047668A (en) * 2000-08-01 2002-02-15 Takenaka Komuten Co Ltd Construction method reutilizing existing pile at re- erection and building structure reutilizing existing pile
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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2012246656A (en) * 2011-05-26 2012-12-13 Takenaka Komuten Co Ltd Foundation structure of building and method for constructing foundation of building
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JP2017036572A (en) * 2015-08-07 2017-02-16 清水建設株式会社 Foundation structure of new structure using existing pile and construction method thereof
JP2017179751A (en) * 2016-03-28 2017-10-05 旭化成ホームズ株式会社 Foundation structure and building
JP2019085787A (en) * 2017-11-08 2019-06-06 株式会社大林組 Demolishing method
JP7013800B2 (en) 2017-11-08 2022-02-01 株式会社大林組 Dismantling method

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