JP2013221310A - Foundation structure and method for constructing foundation - Google Patents

Foundation structure and method for constructing foundation Download PDF

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JP2013221310A
JP2013221310A JP2012093185A JP2012093185A JP2013221310A JP 2013221310 A JP2013221310 A JP 2013221310A JP 2012093185 A JP2012093185 A JP 2012093185A JP 2012093185 A JP2012093185 A JP 2012093185A JP 2013221310 A JP2013221310 A JP 2013221310A
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foundation
sandbag
pile
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adjustment layer
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JP5984083B2 (en
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Yuichi Mazaki
雄一 真崎
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Grape Co Ltd
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Abstract

PROBLEM TO BE SOLVED: To provide a foundation structure and a method for constructing a foundation capable of limiting an inclination of a building even when the ground liquefies and reducing seismic response.SOLUTION: A foundation structure comprises: a foundation body 3 connected to a building body (a superstructure) 2 of a building 1; a weight adjustment layer 5 arranged between the foundation body 3 and the ground G; and a plurality of pile bodies 6 extended in a manner that penetrates the weight adjustment layer 5 into the ground G below the same. The pile body 6 has: a permeable bag (an outer face material) 61 which forms an outer face of the pile body 6; and a plurality of sandbag materials 62 layered inside the bag 61. The sandbag material 62 is configured by packing granular materials in a permeable sandbag which has predetermined dimensions. With the weight adjustment layer 5, the foundation structure can prevent a foundation from being floated by excessive buoyant force by balancing between the buoyant force due to excess pour pressure when the ground G liquefies and a weight of a whole building.

Description

本発明は、基礎構造及び基礎の構築方法に係り、特に、建物の上部構造と連結される基礎本体と、該基礎本体から下方の地盤内に延びて設けられる杭体と、を備えた基礎構造、その基礎構造に係る基礎の構築方法に関するものである。   The present invention relates to a foundation structure and a foundation construction method, and in particular, a foundation structure provided with a foundation body connected to an upper structure of a building, and a pile body provided to extend from the foundation body into a lower ground. It relates to the construction method of the foundation related to the foundation structure.

従来、建物として比較的小規模な戸建住宅の基礎としては、べた基礎や布基礎、独立基礎など、地盤上に直接載置される直接基礎が一般的であった。このような直接基礎の場合、その載置される地盤が軟弱地盤であったり地震時に液状化を起こす可能性がある地盤であったりすると、地盤そのものが支持力を失い、基礎及び建物が傾斜してしまうことがある。このように基礎を含めた建物全体が傾斜してしまうと、その補修が大掛かりになって補修費用も多大となるため、軟弱地盤や液状化地盤にも対応可能な基礎構造が提案されている（例えば、特許文献１、２参照）。   Conventionally, as a foundation of a relatively small detached house as a building, a direct foundation placed directly on the ground such as a solid foundation, a cloth foundation, and an independent foundation has been generally used. In the case of such a direct foundation, if the ground on which it is placed is a soft ground or a ground that may cause liquefaction in the event of an earthquake, the ground itself loses its supporting force, and the foundation and the building are inclined. May end up. If the entire building including the foundation inclines in this way, the repair becomes large and the repair cost becomes large, so a foundation structure that can handle soft ground and liquefied ground has been proposed ( For example, see Patent Documents 1 and 2).

特許文献１に記載の基礎構造は、建物（構造物）の底版から地盤中に貫入させた支持体（杭部）と、この支持体に設けられた浮力体と、支持体に連結されて支持層に設けられたアンカー体と、を備える。この基礎構造は、地盤が液状化して支持力が低下し、過剰間隙水圧により地下水が上昇した場合でも、この地下水による浮力を浮力体に作用させて支持力を得るとともに、アンカー体によって建物の傾きを防止しようとする技術である。   The foundation structure described in Patent Document 1 is supported by being connected to a support body (pile part) that penetrates into the ground from the bottom plate of a building (structure), a buoyancy body provided on the support body, and the support body. An anchor body provided in the layer. In this foundation structure, even if the ground is liquefied and the bearing capacity is reduced, and groundwater rises due to excessive pore water pressure, the buoyancy due to this groundwater acts on the buoyant body to obtain the bearing capacity, and the anchor body tilts the building. It is a technology that tries to prevent.

特許文献２に記載の基礎構造は、建物を支持する基礎と、この基礎の側面を囲んで地盤に貫入された矢板と、基礎の下側かつ矢板で囲まれた領域に設けられる軽量材と、を備える。この基礎構造は、地盤が液状化して支持力が低下した場合に、基礎と矢板を一体的に挙動させることで、基礎及び建物の傾きを抑制し、地下水が上昇した場合にも、軽量材を介して地下水の浮力を基礎に作用させることで、支持力を確保しようとする技術である。   The foundation structure described in Patent Document 2 includes a foundation that supports a building, a sheet pile that surrounds the side of the foundation and penetrates into the ground, and a lightweight material that is provided in an area surrounded by the sheet pile below the foundation, Is provided. In this foundation structure, when the ground is liquefied and the bearing capacity is reduced, the foundation and the sheet pile are made to behave in an integrated manner, thereby suppressing the inclination of the foundation and the building. It is a technology that tries to secure the supporting force by acting on the foundation of the buoyancy of groundwater.

特開平６−２４０６９４号公報JP-A-6-240694 特開２００８−１０１３７９号公報JP 2008-101379 A

しかしながら、特許文献１に記載された基礎構造のように、地盤中に浮力体とアンカー体とを構築するためには、その施工が非常に大掛かりになってしまい、コスト増加が避けられず、比較的小規模な戸建住宅への適用が困難である。また、特許文献２に記載された基礎構造のように、基礎を矢板で囲むとともに、その囲まれた領域に軽量材を設けると、地下水が常に滞留することとなって、滞留した地下水が腐敗あるいは劣化することがある。また、地盤が液状化した際の地下水の浮力や、地下水と砂質土とが混濁した流動体の浮力は、力学的に安定したものではないため、浮力体や基礎底面に作用する浮力が一定せず、かつ建物の平面的な位置によっても浮力が異なるために、建物全体の傾きを効果的に抑制することが困難である。   However, as in the foundation structure described in Patent Document 1, in order to construct a buoyancy body and an anchor body in the ground, the construction becomes very large, and an increase in cost is inevitable. It is difficult to apply to small-scale detached houses. Moreover, like the foundation structure described in patent document 2, when a foundation is enclosed with a sheet pile and a lightweight material is provided in the enclosed area, groundwater will always stay, and the retained groundwater will rot or May deteriorate. In addition, the buoyancy of the groundwater when the ground is liquefied and the buoyancy of the fluid in which the groundwater and sandy soil are turbid are not mechanically stable. In addition, since the buoyancy varies depending on the planar position of the building, it is difficult to effectively suppress the inclination of the entire building.

したがって、本発明は、地盤が液状化した場合であっても建物の傾きを抑制するとともに地震応答を低減させることができる基礎構造及び基礎の構築方法を提供することを目的とする。   Accordingly, an object of the present invention is to provide a foundation structure and a foundation construction method capable of suppressing the inclination of the building and reducing the seismic response even when the ground is liquefied.

上記目的を達成するために請求項１に記載の基礎構造は、建物の上部構造と連結される基礎本体と、前記基礎本体と地盤との間に設けられる重量調整層と、前記重量調整層から下方の地盤中に貫入して延びる複数の杭体と、を備え、前記杭体は、該杭体の外面を形成するとともに透水性を有した外面材と、該外面材の内部に積層された複数の土嚢材と、を備え、該土嚢材は、透水性を有した所定寸法の土嚢袋に粒状物を詰めて構成されていることを特徴とする。   In order to achieve the above object, the foundation structure according to claim 1 includes a foundation body connected to an upper structure of a building, a weight adjustment layer provided between the foundation body and the ground, and the weight adjustment layer. A plurality of pile bodies penetrating and extending into the lower ground, the pile bodies forming an outer surface of the pile body and having a water permeability and laminated inside the outer surface material A plurality of sandbag materials, wherein the sandbag materials are configured by packing granular materials in sandbag bags of a predetermined size having water permeability.

請求項２に記載の基礎構造は、請求項１に記載された基礎構造において、前記上部構造から前記複数の杭体までを含めた建物の全体重量と、前記基礎本体から前記重量調整層及び前記杭体までを含めた地中部の排土体積と、によって算出される密度（全体重量／排土体積）が略１．０ｔ／ｍ3〜１．５ｔ／ｍ3となるように前記重量調整層の比重が設定されていることを特徴とする。 The foundation structure according to claim 2 is the foundation structure according to claim 1, wherein the entire weight of the building including the upper structure to the plurality of pile bodies, the weight adjustment layer, and the the weight adjustment layer as the density calculated and soil discharge volume of underground portion including up to the pile body, the (total weight / earth removal volume) is substantially 1.0t / m 3 ~1.5t / m 3 The specific gravity of is set.

請求項３に記載の基礎構造は、請求項１又は２に記載された基礎構造において、前記重量調整層は、事後発泡性コンクリートから構成されるとともに、該重量調整層の比重が０．５〜１．０の範囲に設定されていることを特徴とする。   The foundation structure according to claim 3 is the foundation structure according to claim 1 or 2, wherein the weight adjustment layer is composed of post-expandable concrete, and the weight adjustment layer has a specific gravity of 0.5 to 0.5. It is characterized by being set to a range of 1.0.

請求項４に記載の基礎構造は、請求項１〜３のいずれか一項に記載された基礎構造において、前記基礎本体と前記重量調整層との間には、複数の土嚢材を積層して構成される透水層が設けられ、該透水層の下面に前記杭体の杭頭部が連続して設けられていることを特徴とする。   The foundation structure according to claim 4 is the foundation structure according to any one of claims 1 to 3, wherein a plurality of sandbag materials are laminated between the foundation main body and the weight adjustment layer. The permeable layer comprised is provided, The pile head of the said pile body is continuously provided in the lower surface of this permeable layer, It is characterized by the above-mentioned.

請求項５に記載の基礎の構築方法は、請求項１〜４のいずれか一項に記載の基礎構造に係る基礎の構築方法であって、前記杭体の寸法に応じて地盤を掘削し、掘削した掘削孔に前記杭体の外面材をセットし、セットした外面材に前記複数の土嚢材を投入し、該土嚢材を積層して前記杭体を構築し、前記基礎本体及び前記重量調整層が構築される領域の地盤を掘削し、掘削して露出した前記杭体の杭頭部と一体的に前記重量調整層を構築し、構築した該重量調整層の上面部に前記杭体の外面材を接続してから、前記杭体及び前記重量調整層の上側に前記基礎本体を構築することを特徴とする。   The foundation construction method according to claim 5 is a foundation construction method according to any one of claims 1 to 4, wherein the ground is excavated according to the dimensions of the pile body, The outer surface material of the pile body is set in the excavated excavation hole, the plurality of sandbag materials are put into the set outer surface material, and the pile body is constructed by stacking the sandbag materials, and the foundation body and the weight adjustment Excavating the ground in the region where the layer is constructed, constructing the weight adjustment layer integrally with the pile head of the pile body exposed by excavation, and placing the pile body on the upper surface of the constructed weight adjustment layer After connecting an outer surface material, the said base main body is constructed | assembled above the said pile body and the said weight adjustment layer, It is characterized by the above-mentioned.

請求項６に記載の基礎の構築方法は、請求項５に記載された基礎の構築方法において、前記重量調整層の上面部に前記杭体の外面材を接続した後に、前記杭体及び前記重量調整層の上側に複数の土嚢材を積層して透水層を形成してから、形成した該透水層の上側に前記基礎本体を構築することを特徴とする。   The foundation construction method according to claim 6 is the foundation construction method according to claim 5, wherein after the outer surface material of the pile body is connected to the upper surface portion of the weight adjustment layer, the pile body and the weight. A plurality of sandbag materials are laminated on the upper side of the adjustment layer to form a water permeable layer, and then the foundation body is constructed on the upper side of the formed water permeable layer.

請求項１に記載された発明によれば、基礎本体と地盤との間に重量調整層を設けたことで、地盤が液状化した場合の過剰間隙水圧による浮力と建物全体の重量とをバランスさせ、過大な浮力による基礎の浮き上がりを防止することができる。また、重量調整層から下方の地盤中に延びる複数の杭体を設けたことで、常時の鉛直荷重を杭体で支持するとともに、液状化による浮力が局部的に過大に作用したとしても、杭体の引き抜き抵抗力によって浮力に抵抗することができ、建物の傾きを抑制することができる。さらに、透水性を有した外面材と、その内部に積層された複数の土嚢材と、を備えて杭体が構成され、透水性を有した土嚢袋に粒状物を詰めて土嚢材が構成されているので、透水性を有した杭体を構築することができる。また、外面材の内部に土嚢材を積層して杭体が構築できるので、鉄筋コンクリート製の杭（場所打ち杭やＰＣ杭）あるいは鋼管杭などと比較して、安価かつ容易な施工手順で杭体を構築することができる。   According to the invention described in claim 1, by providing a weight adjustment layer between the foundation body and the ground, the buoyancy due to excess pore water pressure when the ground is liquefied and the weight of the entire building are balanced. It is possible to prevent the foundation from being lifted due to excessive buoyancy. In addition, by providing a plurality of pile bodies that extend from the weight adjustment layer into the ground below, even if the normal vertical load is supported by the pile bodies and the buoyancy caused by liquefaction is locally excessive, It can resist buoyancy by pulling resistance of the body, and can suppress the inclination of the building. Furthermore, a pile body is configured by including an outer surface material having water permeability and a plurality of sandbag materials laminated inside, and a sandbag material is configured by packing granular material in a water bag having water permeability. Therefore, the pile body with water permeability can be constructed. In addition, because piles can be constructed by laminating sandbag materials inside the outer surface material, pile bodies can be constructed with cheaper and easier construction procedures compared to reinforced concrete piles (cast-in-place piles or PC piles) or steel pipe piles. Can be built.

さらに、外面材の内部に土嚢材が積層されていることから、建物の鉛直荷重を土嚢材間で伝達して鉛直支持力を発揮することができるとともに、地震時に液状化して軟弱化した地盤に過大なせん断変位が生じた場合には、上下の土嚢材同士が左右にずれることで免震効果を発揮するとともに、積層した土嚢材がその周囲を外面材で拘束されていることから、地盤のせん断変位に追従して杭体が変形することができ、杭体の破損を防止することができる。そして、地震後には杭体が初期状態に復帰して所定の鉛直支持力で建物を支持することで、建物の傾きを効果的に抑制することができる。なお、土嚢材の土嚢袋に詰める粒状物としては、土や砂、砕石等に限らず、ガラス片や樹脂片等であってもよく、化学変化や継時変化が少ない素材であって耐荷重性に優れたものが好ましい。   In addition, because sandbags are laminated inside the exterior material, the vertical load of the building can be transmitted between the sandbags to exert vertical support, and the ground that has become liquefied and softened during an earthquake When an excessive shear displacement occurs, the upper and lower sandbag materials are shifted to the left and right to exert a seismic isolation effect, and since the laminated sandbag materials are constrained by the outer surface material, The pile body can be deformed following the shear displacement, and damage to the pile body can be prevented. Then, after the earthquake, the pile body returns to the initial state and supports the building with a predetermined vertical supporting force, so that the inclination of the building can be effectively suppressed. In addition, the granular material to be packed in the sandbag bag of sandbag material is not limited to soil, sand, crushed stone, etc., but may be a piece of glass, a piece of resin, etc. Those excellent in properties are preferred.

請求項２に記載された発明によれば、重量調整層の比重を適宜に設定することによって、建物の全体重量を排土体積で除した密度を略１．０ｔ／ｍ3〜１．５ｔ／ｍ3とすることで、液状化による浮力に対して浮き上がりを生じさせず、かつ、浮力と建物重量とをバランスさせて建物の傾きを抑制することができる。また、地盤の表層部分が液状化する場合であっても、この液状化層よりも深い非液状化層まで杭体の先端部を貫入させておくことにより、杭体自体の鉛直支持力及び引き抜き抵抗力を残存させることができ、建物の転倒や傾斜を防止することができる。 According to the invention described in claim 2, by setting the specific gravity of the weight adjusting layer appropriately, the density obtained by dividing the total weight of the building by the soil volume is approximately 1.0 t / m 3 to 1.5 t / m. By setting to m 3 , it is possible to suppress the inclination of the building without causing buoyancy due to liquefaction and balancing the buoyancy and the building weight. Moreover, even when the surface layer portion of the ground is liquefied, the vertical supporting force and pulling-out of the pile body itself can be obtained by penetrating the tip of the pile body to a non-liquefied layer deeper than this liquefied layer. Resisting force can remain, and the building can be prevented from falling or tilting.

請求項３に記載された発明によれば、事後発泡性コンクリートから重量調整層を構成することで、重量調整層を比較的容易かつ安価に構築することができる。さらに、重量調整層の比重を０．５〜１．０の範囲に設定することによって、上部構造の規模や構造種別等に応じて重量調整層の重量を調整することができる。即ち、上部構造の重量が小さい建物であれば、重量調整層の比重を大きく設定し、上部構造の重量が大きい建物であれば、重量調整層の比重を小さく設定することで、建物全体の重量を調整するとともに、重量調整層の厚さ寸法を適宜に設定して排土体積を調整することができる。従って、液状化による浮力とバランスするように建物重量と排土体積とを調整する際の調整幅を拡大することができ、本発明の基礎構造の適用範囲を拡大させることができる。   According to the invention described in claim 3, the weight adjusting layer can be constructed relatively easily and inexpensively by constituting the weight adjusting layer from the post-expandable concrete. Furthermore, by setting the specific gravity of the weight adjustment layer in the range of 0.5 to 1.0, the weight of the weight adjustment layer can be adjusted according to the scale of the upper structure, the structure type, and the like. In other words, if the weight of the superstructure is small, the specific gravity of the weight adjustment layer is set large. If the weight of the superstructure is large, the specific weight of the weight adjustment layer is set small. And adjusting the thickness of the weight adjusting layer appropriately to adjust the volume of soil removed. Therefore, the adjustment range when adjusting the building weight and the soil removal volume so as to balance the buoyancy due to liquefaction can be expanded, and the application range of the basic structure of the present invention can be expanded.

請求項４に記載された発明によれば、基礎本体と重量調整層との間に透水層を設け、この透水層に杭体の杭頭部を連続させたことで、透水性を有した杭体と透水層とに亘って通水させることができる。従って、地盤の液状化によって発生した地下水を杭体及び透水層を介して地上へ排水することができ、地下水による過大な浮力が基礎本体等に作用することを防止して、不均一な浮力による建物の傾きを抑制することができる。さらに、地盤中に地下水が滞留することがなく、その腐敗や劣化を防止することができる。また、複数の土嚢材を積層して透水層が構成されているので、土嚢材同士の隙間が土砂で埋まったとしても、土嚢袋及び内部の粒状物による透水性が確保でき、地下水を地上に排水することができる。   According to the invention described in claim 4, a water permeable pile is provided by providing a water permeable layer between the foundation main body and the weight adjusting layer, and by continuing the pile head of the pile body to the water permeable layer. Water can be passed over the body and the water-permeable layer. Therefore, groundwater generated by liquefaction of the ground can be drained to the ground through pile bodies and permeable layers, preventing excessive buoyancy due to groundwater from acting on the foundation body, etc. The inclination of the building can be suppressed. Furthermore, groundwater does not stay in the ground, and its decay and deterioration can be prevented. In addition, since a water permeable layer is formed by laminating a plurality of sandbag materials, even if the gap between the sandbag materials is filled with earth and sand, water permeability can be secured by the sandbag bags and the internal granular materials, and the groundwater can be put on the ground. It can be drained.

請求項５に記載された発明によれば、杭体を構築してから地盤を掘削し、杭体の杭頭部と一体的に重量調整層を構築し、その上側に基礎本体を構築することで、杭体と重量調整層とを連結して浮き上がり抵抗力を発揮させることができる。また、掘削孔にセットした外面材に土嚢材を投入して積層することで、落下の衝撃により土嚢材同士を締め固めつつ積層できるとともに、杭体を容易かつ短工期で構築することができる。さらに、構築した重量調整層の上面部に杭体の外面材を接続することで、杭体と重量調整層との一体性を高めることができる。   According to the invention described in claim 5, excavating the ground after constructing the pile body, constructing the weight adjustment layer integrally with the pile head of the pile body, and constructing the foundation main body on the upper side Thus, the pile body and the weight adjusting layer can be connected to raise the floating resistance. Moreover, by inserting and laminating sandbag material on the outer surface material set in the excavation hole, the sandbag materials can be laminated while being compacted by impact of dropping, and a pile body can be constructed easily and in a short construction period. Furthermore, the integrity of a pile body and a weight adjustment layer can be improved by connecting the outer surface material of a pile body to the upper surface part of the constructed weight adjustment layer.

なお、重量調整層の強度や硬さによっては、重量調整層を構築してから、この重量調整層を貫通して地盤を掘削し、この掘削孔に外面材をセットするとともに土嚢材を投入して杭体を構築してもよい。即ち、例えば、比重１．０以下さらには比重０．５〜０．７程度の軽量発泡コンクリート等で重量調整層を構成する場合には、一般的な掘削機械（オーガー等）を用いて重量調整層を貫通することができる。このように重量調整層を構築してから掘削することで、杭芯位置の墨出しや掘削機械の設置及び掘削作業などを良好な作業環境で実施することができる。   Depending on the strength and hardness of the weight adjustment layer, after constructing the weight adjustment layer, excavate the ground through this weight adjustment layer, set the outer surface material in this excavation hole and insert sandbag material You may build a pile. That is, for example, when the weight adjustment layer is made of lightweight foamed concrete having a specific gravity of 1.0 or less and a specific gravity of about 0.5 to 0.7, the weight is adjusted using a general excavating machine (eg auger). It can penetrate the layer. Thus, by excavating after constructing the weight adjustment layer, it is possible to implement the marking of the pile core position, the installation of the excavating machine, the excavation work, and the like in a favorable work environment.

請求項６に記載された発明によれば、杭体及び重量調整層の上側に複数の土嚢材を積層して透水層を形成してから、その上側に基礎本体を構築することで、杭体と透水層とを確実に接続して杭体から透水層を介して地下水を排水することができる。   According to the invention described in claim 6, the pile body is formed by laminating a plurality of sandbag materials on the upper side of the pile body and the weight adjustment layer to form a water permeable layer, and then constructing the foundation main body on the upper side. The groundwater can be drained from the pile body through the water permeable layer by securely connecting the water permeable layer and the water permeable layer.

本発明の一実施形態に係る建物の基礎構造を示す斜視図である。It is a perspective view which shows the foundation structure of the building which concerns on one Embodiment of this invention. 前記建物の下部を示す縦断面図である。It is a longitudinal cross-sectional view which shows the lower part of the said building. 前記建物の基礎部分の横断面図である。It is a cross-sectional view of the foundation part of the building. 前記基礎の作用を説明する拡大断面図である。It is an expanded sectional view explaining the effect | action of the said foundation. 前記建物の基礎を構築する構築手順を示す断面図である。It is sectional drawing which shows the construction procedure which builds the foundation of the said building. 図５に続く前記基礎の構築手順を示す断面図である。It is sectional drawing which shows the construction procedure of the said foundation following FIG. 図６に続く前記基礎の構築手順を示す断面図である。It is sectional drawing which shows the construction procedure of the said foundation following FIG. 図７に続く前記基礎の構築手順を示す断面図である。It is sectional drawing which shows the construction procedure of the said foundation following FIG. 基礎の構築手順の変形例を示す断面図である。It is sectional drawing which shows the modification of the construction procedure of a foundation.

以下、本発明の一実施形態にかかる基礎構造を、図１〜図３に基づいて説明する。本実施形態に係る基礎構造は、建物１の上部構造としての建物本体２を支持するものであって、建物１は、戸建住宅やアパート等に利用されるものである。この建物１は、地盤Ｇ上に構築され、この地盤Ｇを地表ＧＬから鉛直方向であるＺ方向下方に掘削して、後述する基礎本体３、透水層４、重量調整層５及び杭体６が構築される。建物本体２は、木造や軽量鉄骨造などの比較的小規模かつ軽量な２〜３階建てであって、水平二方向であるＸ，Ｙ方向に沿った矩形の平面形状を有し、土台２１を介して基礎本体３に固定されている。   Hereinafter, the basic structure concerning one Embodiment of this invention is demonstrated based on FIGS. 1-3. The foundation structure according to the present embodiment supports a building body 2 as an upper structure of the building 1, and the building 1 is used for a detached house, an apartment, or the like. This building 1 is constructed on the ground G, and this ground G is excavated from the surface GL downward in the Z direction, which is a vertical direction, so that a foundation body 3, a permeable layer 4, a weight adjusting layer 5 and a pile body 6 which will be described later are formed. Built. The building body 2 is a relatively small and light 2 to 3 story building such as a wooden structure or a lightweight steel structure, and has a rectangular planar shape along the X and Y directions which are two horizontal directions. It is being fixed to the basic body 3 via.

基礎本体３は、建物本体２の土台２１に沿って設けられる基礎立上り３１と、この基礎立上り３１と一体に連結されて水平面内に延びる基礎底版３２と、を有したべた基礎となっている。基礎底版３２は、例えば、厚さ寸法が２００ｍｍ〜３００ｍｍの鉄筋コンクリート製であり、その下面が厚さ寸法２００ｍｍ程度の砕石層３３を介して透水層４の上側に載置されている。即ち、基礎本体３の根入れ深さ（地表ＧＬから砕石層３３の下面までの距離）は、約２００ｍｍに設定されている。また、基礎立上り３１は、地表ＧＬから上方に４００ｍｍ〜６００ｍｍ程度突出して設けられ、その上端に建物本体２の土台２１がアンカーボルト及び接合金物を介して連結されている。   The foundation main body 3 is a solid foundation having a foundation rising 31 provided along the base 21 of the building main body 2 and a foundation bottom slab 32 integrally connected to the foundation rising 31 and extending in a horizontal plane. The foundation bottom plate 32 is made of, for example, reinforced concrete having a thickness dimension of 200 mm to 300 mm, and its lower surface is placed on the upper side of the water permeable layer 4 via a crushed stone layer 33 having a thickness dimension of about 200 mm. That is, the penetration depth (the distance from the ground surface GL to the lower surface of the crushed stone layer 33) of the foundation body 3 is set to about 200 mm. The foundation rising 31 is provided so as to protrude upward from the ground surface GL by about 400 mm to 600 mm, and the base 21 of the building body 2 is connected to the upper end of the foundation rising 31 via an anchor bolt and a joint hardware.

透水層４は、複数の土嚢材４Ａを積層して構成されるものであって、土嚢材４Ａとしては、例えば、ポリエチレン製等の透水性を有した織布で構成された土嚢袋にガラス片やガラス粒等の粒状物を詰めたものが利用できる。このような土嚢材４Ａとしては、その寸法が４００ｍｍｘ４００ｍｍｘ１００ｍｍ程度であり、その重量が５ｋｇ〜１０ｋｇ程度のものであれば、搬送や積層に係る作業性の面で好適である。また、土嚢材４Ａは、土嚢袋及び粒状物の両方が水を通すことから土嚢材４Ａ自体が透水性を有するとともに、積層した土嚢材４Ａ同士に適度な隙間が形成されることから、この隙間によっても透水性が得られるようになっている。   The water permeable layer 4 is configured by laminating a plurality of sandbag materials 4A. As the sandbag material 4A, for example, a glass piece is placed on a sandbag bag made of a woven fabric having water permeability such as polyethylene. And those filled with granular materials such as glass grains can be used. As such a sandbag material 4A, if the dimension is about 400 mm × 400 mm × 100 mm and the weight is about 5 kg to 10 kg, it is preferable in terms of workability related to conveyance and lamination. In addition, since the sandbag material 4A allows both the sandbag bag and the granular material to pass water, the sandbag material 4A itself has water permeability, and an appropriate gap is formed between the stacked sandbag materials 4A. The water permeability can be obtained.

このような透水層４は、基礎本体３と重量調整層５との間において、これらの基礎本体３及び重量調整層５と略同一の平面範囲に設けられている。具体的には、重量調整層５の上面に土嚢材４Ａを三段積層して透水層４が構成され、その層厚が約３００ｍｍに設定されている。また、透水層４及び重量調整層５の周囲には、透水層４と同一の土嚢材４Ａを積層した第二透水層４１が設けられ、この第二透水層４１の上部と透水層４の周縁とが互いに接して通水可能に構成されている。また、第二透水層４１の上側には、溝や排水管などからなる排水路４２が設けられている。この第二透水層４１は、地盤Ｇを掘削して重量調整層５を構築する際の土留め壁として、さらに重量調整層５の側面を形成する型枠としても利用される。   Such a water permeable layer 4 is provided between the foundation main body 3 and the weight adjustment layer 5 in the same plane range as the foundation main body 3 and the weight adjustment layer 5. Specifically, the water permeable layer 4 is formed by laminating three layers of sandbags 4A on the upper surface of the weight adjusting layer 5, and the layer thickness is set to about 300 mm. Further, around the water permeable layer 4 and the weight adjusting layer 5, a second water permeable layer 41 in which the same sandbag material 4 </ b> A as the water permeable layer 4 is laminated is provided, and the upper part of the second water permeable layer 41 and the periphery of the water permeable layer 4. Are configured to allow water to pass through each other. In addition, a drainage channel 42 including a groove, a drainage pipe, and the like is provided above the second water permeable layer 41. The second water permeable layer 41 is also used as a retaining wall when excavating the ground G to construct the weight adjustment layer 5 and as a mold for forming the side surface of the weight adjustment layer 5.

重量調整層５は、掘削した地盤Ｇに事後発泡性コンクリートを打設して構築される。この事後発泡性コンクリートは、生石灰とセメントを主成分とし、微少のアルミニウム粉を含んだ発泡材、発泡促進材及び発泡安定材や他の混和剤等が混入されるとともに、これらを混練水によって混練して構成され、打設された後に地盤Ｇ中の水分を吸収して発泡、膨張し、固化後には気泡を含んだ軽量コンクリートを形成するものである。このように事後発泡性コンクリートが固化して構築される重量調整層５は、発泡材の混入量によって比重が適宜に設定可能であり、この比重としては、０．５〜１．０の範囲に設定されている。また、重量調整層５は、例えば、その層厚が約１ｍに設定されている。なお、重量調整層５の下側には、透水層４と同一の土嚢材４Ａが設けられており、これらの土嚢材４Ａは、事後発泡性コンクリートを打設する前に杭体６部分を除く地盤Ｇの根伐り底に並べて配置されたものである。   The weight adjusting layer 5 is constructed by placing post-expandable concrete on the excavated ground G. This post-expandable concrete is composed mainly of quicklime and cement, and contains a foam material containing a small amount of aluminum powder, a foam accelerator, a foam stabilizer, and other admixtures. After being placed and placed, it absorbs moisture in the ground G and foams and expands, and after solidification, forms lightweight concrete containing air bubbles. Thus, the specific gravity of the weight adjustment layer 5 constructed by solidifying the foamable concrete after the fact can be appropriately set depending on the amount of the foaming material mixed. The specific gravity is in the range of 0.5 to 1.0. Is set. Moreover, the layer thickness of the weight adjusting layer 5 is set to about 1 m, for example. In addition, under the weight adjustment layer 5, the same sandbag material 4A as the water permeable layer 4 is provided, and these sandbag materials 4A remove the pile body 6 part before pouring expandable concrete. They are arranged side by side on the bottom of the ground G.

杭体６は、透水層４の下面から重量調整層５を貫通するとともに下方の地盤Ｇ中に貫入して延びて形成され、基礎本体３の平面形状に応じた範囲内においてＸ，Ｙ方向に適宜な間隔で複数本が設けられている。具体的には、Ｘ方向に沿って３列、Ｙ方向に沿って４列の計１２本の杭体６が設けられている。このような杭体６は、図４にも示すように、当該杭体５の外面を形成するとともに透水性を有した外面材としての袋６１と、この袋６１の内部に積層された土嚢材６２と、を備えて構成されている。袋６１は、例えば、ポリエチレン製等の透水性を有した織布で構成されている。土嚢材６２は、透水層４の土嚢材４Ａと同様に、ポリエチレン製等の透水性を有した織布で構成された土嚢袋にガラス片やガラス粒等の粒状物を詰めたものが利用でき、その形状及び寸法は、例えば、直径６００ｍｍで厚さ２００ｍｍ程度のものが利用できる。また、袋６１の上端縁は、重量調整層５の上面まで延びて重量調整層５に固定されており、透水層４の下面と接触するように土嚢材６２が積層されている。   The pile body 6 extends from the lower surface of the water-permeable layer 4 through the weight adjusting layer 5 and penetrates into the lower ground G and extends in the X and Y directions within the range corresponding to the planar shape of the foundation body 3. A plurality are provided at appropriate intervals. Specifically, a total of 12 pile bodies 6 of 3 rows along the X direction and 4 rows along the Y direction are provided. As shown in FIG. 4, the pile body 6 includes a bag 61 as an outer surface material that forms the outer surface of the pile body 5 and has water permeability, and a sandbag material laminated inside the bag 61. 62. The bag 61 is made of a woven fabric having water permeability such as made of polyethylene, for example. As the sandbag material 62, the sandbag material 62, which is made of a woven cloth having water permeability made of polyethylene or the like, can be used as the sandbag material 62 is filled with granular materials such as glass pieces and glass particles. As the shape and size, for example, a diameter of about 600 mm and a thickness of about 200 mm can be used. The upper edge of the bag 61 extends to the upper surface of the weight adjustment layer 5 and is fixed to the weight adjustment layer 5, and a sandbag material 62 is laminated so as to contact the lower surface of the water permeable layer 4.

このような杭体６は、袋６１及び土嚢材６２の両方が水を通すことから杭体６自体が透水性を有し、杭体６の上端と透水層４の下面とが連続して設けられていることから、杭体６内部を透過した水を透水層４から第二透水層４１及び排水路４２に排水できるように構成されている。また、袋６１内部に土嚢材６２が積層されていることから、土嚢材６２同士が左右にずれるように移動することで、杭体６がせん断変形可能になっており、軟弱地盤や液状化地盤における地震時の地盤Ｇの変位に杭体６が追従できるようになっている。さらに、土嚢材６２同士が左右にずれるように移動することから、地盤Ｇから入力する地震動が杭体６を介して上方に伝達されにくくなり、杭体６による免震効果を得ることもできる。この際、積層された土嚢材６２が袋６１によって拘束されているので、左右にずれたとしても土嚢材６２同士が分離せず、地震後には杭体６を初期状態に復帰させることができるようになっている。   In such a pile body 6, since both the bag 61 and the sandbag 62 pass water, the pile body 6 itself has water permeability, and the upper end of the pile body 6 and the lower surface of the water permeable layer 4 are provided continuously. Therefore, the water that has passed through the inside of the pile body 6 can be drained from the water permeable layer 4 to the second water permeable layer 41 and the drainage channel 42. Moreover, since the sandbag material 62 is laminated | stacked inside the bag 61, when the sandbag material 62 moves so that it may shift | deviate to right and left, the pile body 6 can be shear-deformed, and soft ground or liquefied ground The pile body 6 can follow the displacement of the ground G during the earthquake. Furthermore, since the sandbag materials 62 move so as to be shifted from side to side, the seismic motion input from the ground G is hardly transmitted upward via the pile body 6, and the seismic isolation effect by the pile body 6 can be obtained. At this time, since the laminated sandbag material 62 is restrained by the bag 61, the sandbag materials 62 are not separated from each other even if they are shifted left and right, and the pile body 6 can be returned to the initial state after the earthquake. It has become.

以上のように本実施形態の基礎構造では、基礎本体３、透水層４及び重量調整層５を合わせた基礎の根入れ深さ（地表ＧＬから重量調整層５の下面までの距離）は、例えば、約１．５ｍに設定されている。ここで、基礎の根入れ深さは、液状化時に生じる地下水の水圧によって重量調整層５の下面に作用する浮力と、建物本体２、基礎本体３、透水層４、重量調整層５及び杭体６の重量と、を比較して設定されていればよい。具体的には、建物本体２、基礎本体３、透水層４、重量調整層５及び杭体６を含む建物１の全体重量Ｗを、重量調整層５の下面まで掘削した排土体積Ｖで除した密度Ｐ（Ｐ＝Ｗ／Ｖ）が１．０〜１．５（ｔ／ｍ3）の範囲となるように、重量調整層５の比重と層厚とが設定されている。従って、液状化により生じた地下水が地表ＧＬまで上昇した場合であっても、重量調整層５の下面に作用する浮力が建物１の全体重量Ｗを上回ることがなく、建物１の浮き上がりが防止できるようになっている。 As described above, in the foundation structure of the present embodiment, the base penetration depth (distance from the ground surface GL to the lower surface of the weight adjustment layer 5) of the foundation body 3, the water permeable layer 4, and the weight adjustment layer 5 is, for example, , About 1.5 m. Here, the penetration depth of the foundation is the buoyancy acting on the lower surface of the weight adjustment layer 5 due to the groundwater pressure generated during liquefaction, the building body 2, the foundation body 3, the water permeable layer 4, the weight adjustment layer 5 and the pile body. It is sufficient that the weight is set by comparing the weight of 6. Specifically, the total weight W of the building 1 including the building body 2, the foundation body 3, the water permeable layer 4, the weight adjustment layer 5 and the pile body 6 is divided by the soil volume V excavated to the lower surface of the weight adjustment layer 5. The specific gravity and the layer thickness of the weight adjusting layer 5 are set so that the density P (P = W / V) is in the range of 1.0 to 1.5 (t / m 3 ). Therefore, even when the groundwater generated by liquefaction rises to the ground surface GL, the buoyancy acting on the lower surface of the weight adjustment layer 5 does not exceed the overall weight W of the building 1 and can prevent the building 1 from being lifted. It is like that.

以上のような基礎構造の施工手順について図５〜図８も参照して説明する。先ず、杭体６の施工位置及び杭長に応じて、図５（Ａ）に示すように、アースドリル等の掘削装置Ｍ１を用いて地表ＧＬから地盤Ｇを掘削し、掘削孔Ｄを形成する。次に、図５（Ｂ）に示すように、掘削孔Ｄに袋６１を挿入し、袋６１の上端部を地表面に仮固定する。次に、図６（Ａ）に示すように、土嚢材６２を袋６１内部に投入し、袋６１の先端部から上方に向かって土嚢材６２を積層していく。この際、土嚢材６２は、落下の衝撃により上下方向に潰れるとともに平面内に広がるように変形し、上下の土嚢材６２同士が密接され、かつこれ袋６１を掘削孔Ｄの径方向に拡げつつ積層される。ここで、所定数の土嚢材６２を投入したら必要に応じて、図６（Ｂ）に示すように、バイブレータ等の締固装置Ｍ２を袋６１内部に挿入し、この締固装置Ｍ２によって土嚢材６２同士及び土嚢材６２内の粒状物に振動を加えて締め固める。このように土嚢材６２の投入を繰り返し、透水層４の下面位置まで土嚢材６２を積層して杭体６を構築する。   The construction procedure of the foundation structure as described above will be described with reference to FIGS. First, according to the construction position of the pile body 6 and the pile length, as shown in FIG. 5 (A), the ground G is excavated from the ground surface GL using the excavating device M1 such as an earth drill to form the excavation hole D. . Next, as shown in FIG. 5B, the bag 61 is inserted into the excavation hole D, and the upper end of the bag 61 is temporarily fixed to the ground surface. Next, as shown in FIG. 6A, the sandbag material 62 is put into the bag 61, and the sandbag material 62 is stacked upward from the front end portion of the bag 61. At this time, the sandbag material 62 is deformed so as to be crushed in the vertical direction and spread in the plane by the impact of the drop, the upper and lower sandbag materials 62 are brought into close contact with each other, and the bag 61 is expanded in the radial direction of the excavation hole D Laminated. Here, when a predetermined number of sandbag materials 62 are inserted, as shown in FIG. 6B, a compacting device M2 such as a vibrator is inserted into the bag 61 as necessary, and the sandbag material is inserted by the compacting device M2. The particles 62 and the granular material in the sandbag material 62 are vibrated and compacted. In this manner, the sandbag material 62 is repeatedly charged, and the sandbag material 62 is stacked up to the lower surface position of the water permeable layer 4 to construct the pile body 6.

次に、図７（Ａ）に示すように、地盤Ｇを掘削して根伐り底Ｄ１から杭体６の上部を露出させたら、透水層４の下面位置（重量調整層５の上面位置）で袋６１を切断し、切断した袋６１Ａを除去する。さらに、根伐り底Ｄ１に土嚢材４Ａを並べるとともに、根伐った側面Ｄ２に沿って土嚢材４Ａを積層して第二透水層４１を形成する。次に、図７（Ｂ）に示すように、根伐り底Ｄ１の土嚢材４Ａ及び側面Ｄ２の第二透水層４１で囲まれ空間に事後発泡性コンクリートを打設し、事後発泡性コンクリートに地中の水分を吸収させて発泡させて重量調整層５を構築する。この際、所定の発泡状態となるように、散水等により事後発泡性コンクリートに水を供給してもよいし、地下水が多い場合には、根伐り底Ｄ１や側面Ｄ２を遮水して事後発泡性コンクリートが吸収する水分量を調整するようにしてもよい。この事後発泡性コンクリートが発泡して硬化したら、構築された重量調整層５の上面に杭体６の袋６１をビス等の固着材６３で固定し、重量調整層５と杭体６とを一体に接続する。   Next, as shown in FIG. 7A, after excavating the ground G and exposing the upper part of the pile body 6 from the root cutting bottom D1, the bottom surface position of the permeable layer 4 (upper surface position of the weight adjustment layer 5). The bag 61 is cut and the cut bag 61A is removed. Further, the sandbag material 4A is arranged on the root cutting bottom D1, and the sandbag material 4A is laminated along the rooted side surface D2 to form the second water permeable layer 41. Next, as shown in FIG. 7 (B), post-expandable concrete is placed in the space surrounded by the sandbag material 4A of the root cut bottom D1 and the second water permeable layer 41 of the side surface D2, and the post-expandable concrete is grounded. The weight adjustment layer 5 is constructed by absorbing the moisture in the inside and foaming. At this time, water may be supplied to the post-expandable concrete by watering or the like so that a predetermined foaming state is obtained, and when there is a lot of groundwater, the root cutting bottom D1 and the side surface D2 are blocked and the post-foaming is performed. You may make it adjust the moisture content which a property concrete absorbs. After the foamable concrete is foamed and cured, the bag 61 of the pile body 6 is fixed to the upper surface of the constructed weight adjustment layer 5 with a fixing material 63 such as a screw, and the weight adjustment layer 5 and the pile body 6 are integrated. Connect to.

次に、図８に示すように、重量調整層５の上面に土嚢材４Ａを並べて積層し、透水層４を形成する。この積層作業は、人手によって行ってもよいし、適宜な装置あるいは重機を用いて行ってもよい。次に、透水層４の上側に基礎本体２を構築して基礎構造の構築が完了したら、基礎立上り３１の上に建物本体２を構築して建物１を完成させる。   Next, as shown in FIG. 8, the sandbag material 4 </ b> A is arranged and laminated on the upper surface of the weight adjusting layer 5 to form the water permeable layer 4. This stacking operation may be performed manually, or may be performed using an appropriate apparatus or heavy equipment. Next, when the foundation body 2 is constructed on the upper side of the water permeable layer 4 and the construction of the foundation structure is completed, the building body 2 is constructed on the foundation rising 31 to complete the building 1.

本実施形態によれば、基礎本体３及び透水層４と地盤Ｇとの間に重量調整層５が設けられ、この重量調整層５の比重を適宜に調節することで、建物１の全体重量Ｗに基づく地中部の密度Ｐ（＝Ｗ／Ｖ）を所定の値に設定することができる。従って、地盤Ｇが液状化した場合の過剰間隙水圧による浮力が重量調整層５の下面に作用した場合において、この浮力と建物１の全体重量Ｗとをバランスさせ、過大な浮力による建物１の浮き上がりを防止することができる。また、地盤Ｇに貫入した複数の杭体６が設けられているので、常時の鉛直荷重を杭体６で支持するとともに、液状化による浮力が局部的に過大に作用したとしても、杭体６の引き抜き抵抗力によって浮力に抵抗することができ、建物１の傾きを抑制することができる。さらに、杭体６が袋６１とその内部に積層した土嚢材６２とで構成されているので、地震時に液状化して軟弱化した地盤Ｇに過大なせん断変位が生じたとしても、上下の土嚢材６２同士が左右にずれることで免震効果を発揮するとともに、積層した土嚢材６２がその周囲を袋６１で拘束されていることから、地盤Ｇのせん断変位に追従して杭体６が変形することができ、杭体６の破損を防止することができる。そして、地震後には杭体６が初期状態に復帰して所定の鉛直支持力で建物１を支持することで、建物１の傾きを効果的に抑制することができる。   According to this embodiment, the weight adjustment layer 5 is provided between the foundation body 3 and the water permeable layer 4 and the ground G, and the total weight W of the building 1 is adjusted by appropriately adjusting the specific gravity of the weight adjustment layer 5. The density P (= W / V) of the underground part based on can be set to a predetermined value. Therefore, when the buoyancy due to excess pore water pressure when the ground G is liquefied acts on the lower surface of the weight adjustment layer 5, the buoyancy and the overall weight W of the building 1 are balanced to lift the building 1 due to excessive buoyancy. Can be prevented. In addition, since a plurality of pile bodies 6 penetrating into the ground G are provided, a normal vertical load is supported by the pile bodies 6 and even if buoyancy due to liquefaction acts locally excessively, the pile bodies 6 The resistance to buoyancy can be resisted by the pulling-out resistance, and the inclination of the building 1 can be suppressed. Further, since the pile body 6 is composed of the bag 61 and the sandbag material 62 laminated inside, the upper and lower sandbag materials even if excessive shear displacement occurs in the ground G that has been liquefied and softened during the earthquake. Since the seismic isolation effect is exhibited by shifting 62 to the left and right, and the laminated sandbag material 62 is constrained by the bag 61, the pile body 6 deforms following the shear displacement of the ground G. It is possible to prevent the pile body 6 from being damaged. Then, after the earthquake, the pile body 6 returns to the initial state and supports the building 1 with a predetermined vertical supporting force, so that the inclination of the building 1 can be effectively suppressed.

また、透水性を有した袋６１と複数の土嚢材６２とで構成された杭体６自体が透水性を有するとともに、その上側に連続して透水層４が設けられているので、地震時に地盤Ｇが液状化して地下水が上昇した場合であっても、杭体６内部を通して透水層４へ地下水を送って地表ＧＬに排水することができる。従って、地下水による過大な浮力が作用することを防止して、不均一な浮力による建物１の傾きを抑制することができるとともに、地盤Ｇ中に地下水が滞留することがなく、その腐敗や劣化を防止することができる。さらに、袋６１の内部に土嚢材６２を投入して積層することによって杭体６が構築できるので、安価かつ容易な施工手順で杭体６を構築することができ、施工コストの抑制と工期短縮とを図ることができる。さらに、杭体６の施工時において、投入した土嚢材６２の落下の衝撃によって土嚢材６２を締め固めることができるので、袋６１による土嚢材６２の拘束度を高めて、地震時における杭体６の変形追従性を向上させることができるとともに、地震後に初期状態へ復帰しやすくして杭体６の鉛直支持力を確保することができる。   Moreover, since the pile body 6 itself comprised of the bag 61 having water permeability and the plurality of sandbag materials 62 has water permeability, and the water-permeable layer 4 is continuously provided on the upper side thereof, the ground during an earthquake is provided. Even when G is liquefied and the groundwater rises, the groundwater can be sent to the permeable layer 4 through the pile body 6 and drained to the ground surface GL. Accordingly, it is possible to prevent the excessive buoyancy due to the groundwater from acting and to suppress the inclination of the building 1 due to the nonuniform buoyancy, and the groundwater does not stay in the ground G, and its decay and deterioration can be prevented. Can be prevented. Furthermore, since the pile body 6 can be constructed by putting and laminating the sandbag material 62 in the bag 61, the pile body 6 can be constructed by an inexpensive and easy construction procedure, and the construction cost is suppressed and the construction period is shortened. Can be planned. Furthermore, since the sandbag material 62 can be compacted by the impact of the dropped sandbag material 62 during the construction of the pile body 6, the degree of restraint of the sandbag material 62 by the bag 61 is increased, and the pile body 6 in the event of an earthquake. The deformation following ability can be improved, and the vertical support force of the pile body 6 can be secured by facilitating the return to the initial state after the earthquake.

なお、前述した実施形態は本発明の代表的な形態を示したに過ぎず、本発明は、実施形態に限定されるものではない。即ち、本発明の骨子を逸脱しない範囲で種々変形して実施することができる。   In addition, embodiment mentioned above only showed the typical form of this invention, and this invention is not limited to embodiment. That is, various modifications can be made without departing from the scope of the present invention.

例えば、前記実施形態では、基礎本体３の下面全体と重量調整層５との間に透水層４が設けられていたが、これに限らず、透水層４は、杭体６に連続して設けられ、杭体６内部を上昇した地下水を地上に排水できるような経路で設けられていればよい。また、前記実施形態では、透水層４の土嚢材４Ａ及び杭体６の土嚢材６２の土嚢袋、さらには杭体６の袋６１をポリエチレン製等の織布で構成したが、袋の材質等は特に限定されず、透水性を有したものであればよい。また、杭体６を構成する外面材としては、前記実施形態のように袋１６で構成されたものに限らず、パンチングメタルやエキスパンドメタル、金網等を有底円筒形に加工したもので構成されてもよいし、金属以外の網や筒体で構成されていてもよい。さらに、土嚢材４Ａ，６２の粒状物に関しても、ガラス片やガラス粒等で構成されるものに限らず、砕石や樹脂製粒状物などの任意の材料を利用することが可能である。また、前記実施形態では、事後発泡性コンクリートによって重量調整層５を構築したが、重量調整層５を構成する材料は特に限定されるものではなく、比重が１程度以下かつ適宜に調整可能な材料であって、重量調整層５の形態を保持して杭体６との一体性が得られる程度の強度を備えたものであればよい。   For example, in the said embodiment, although the water permeable layer 4 was provided between the whole lower surface of the foundation main body 3, and the weight adjustment layer 5, it does not restrict to this but the water permeable layer 4 is provided in the pile body 6 continuously. It is only necessary to be provided through a route that can drain the groundwater that has risen inside the pile body 6 to the ground. Moreover, in the said embodiment, the sandbag material 4A of the water permeable layer 4 and the sandbag bag of the sandbag material 62 of the pile body 6, and also the bag 61 of the pile body 6 were comprised with the woven fabric made from polyethylene etc., but the material of a bag, etc. Is not particularly limited as long as it has water permeability. Moreover, as an outer surface material which comprises the pile body 6, not only what was comprised by the bag 16 like the said embodiment, but it is comprised by what processed the punching metal, the expanded metal, the wire net, etc. into the bottomed cylindrical shape. Alternatively, it may be composed of a net or cylinder other than metal. Furthermore, regarding the granular material of the sandbag materials 4A and 62, any material such as crushed stone or resin granular material can be used without being limited to glass pieces or glass particles. Moreover, in the said embodiment, although the weight adjustment layer 5 was constructed | assembled by the post-expandable concrete, the material which comprises the weight adjustment layer 5 is not specifically limited, Specific gravity is about 1 or less and the material which can be adjusted suitably And what is necessary is just to have the intensity | strength of the grade which hold | maintains the form of the weight adjustment layer 5 and the integrity with the pile body 6 is acquired.

また、前記実施形態における基礎構造の施工手順としては、杭体６を構築してから地盤Ｇを根伐りして重量調整層５を構築するものであったが、これに限らず、図９に示すような施工手順を採用してもよい。具体的には、杭体６を構築するよりも以前に、地盤Ｇを根伐り底Ｄ１まで掘削し、根伐り底Ｄ１の土嚢材４Ａ及び側面Ｄ２の第二透水層４１で囲まれ空間に事後発泡性コンクリートを打設して重量調整層５を構築する。その後に、重量調整層５の上面にて墨出しを行って杭体６の位置を決めてから、図９（Ａ）に示すように、掘削装置Ｍ１を用いて重量調整層５及び地盤Ｇを掘削し、挿通孔５１及び掘削孔Ｄを形成する。次に、図９（Ｂ）に示すように、挿通孔５１及び掘削孔Ｄに袋６１を挿入し、袋６１の上端部を重量調整層５の上面に固着材６３で固定してから、土嚢材６２を袋６１内部に投入し、袋６１の先端部から上方に向かって土嚢材６２を積層していく。このように土嚢材６２の投入を繰り返し、重量調整層５の上面位置まで土嚢材６２を積層して杭体６を構築する。その後、透水層４及び基礎本体３を構築して基礎構造の施工が完了する。このような施工手順によれば、平坦に形成された重量調整層５の上面にて墨出し作業や杭体６の掘削作業、土嚢材６２の投入作業などを行うことができるので、作業性を向上させることができる。   Moreover, as a construction procedure of the foundation structure in the said embodiment, after constructing the pile body 6, the ground G was rooted and the weight adjustment layer 5 was constructed, but not limited to this, FIG. A construction procedure as shown may be adopted. Specifically, before the pile body 6 is constructed, the ground G is excavated to the root cutting bottom D1, surrounded by the sandbag material 4A of the root cutting bottom D1 and the second permeable layer 41 of the side surface D2, and then after the space. The weight adjusting layer 5 is constructed by placing foaming concrete. Then, after marking on the upper surface of the weight adjustment layer 5 and determining the position of the pile body 6, as shown in FIG. 9A, the weight adjustment layer 5 and the ground G are removed using the excavator M1. The excavation hole 51 and the excavation hole D are formed by excavation. Next, as shown in FIG. 9B, the bag 61 is inserted into the insertion hole 51 and the excavation hole D, and the upper end of the bag 61 is fixed to the upper surface of the weight adjustment layer 5 with the fixing material 63. The material 62 is put into the bag 61, and the sandbag material 62 is stacked from the tip of the bag 61 upward. In this manner, the sandbag material 62 is repeatedly inserted, and the sandbag material 62 is stacked up to the upper surface position of the weight adjustment layer 5 to construct the pile body 6. Thereafter, the water-permeable layer 4 and the foundation main body 3 are constructed, and the construction of the foundation structure is completed. According to such a construction procedure, it is possible to perform the marking work, the excavation work of the pile body 6, the loading work of the sandbag material 62, and the like on the upper surface of the weight adjustment layer 5 formed flat. Can be improved.

１ 建物
２ 建物本体（上部構造）
３ 基礎本体
４ 透水層
４Ａ 土嚢材
５ 重量調整層
６ 杭体
６１ 袋（外面材）
６２ 土嚢材 1 Building 2 Building body (superstructure)
3 foundation body 4 permeable layer 4A sandbag material 5 weight adjustment layer 6 pile body 61 bag (outer surface material)
62 Sandbag Material

Claims (6)

建物の上部構造と連結される基礎本体と、
前記基礎本体と地盤との間に設けられる重量調整層と、
前記重量調整層から下方の地盤中に貫入して延びる複数の杭体と、を備え、
前記杭体は、該杭体の外面を形成するとともに透水性を有した外面材と、該外面材の内部に積層された複数の土嚢材と、を備え、該土嚢材は、透水性を有した所定寸法の土嚢袋に粒状物を詰めて構成されていることを特徴とする基礎構造。 A foundation body connected to the superstructure of the building;
A weight adjusting layer provided between the foundation body and the ground;
A plurality of pile bodies extending through and penetrating from the weight adjustment layer into the ground below,
The pile body includes an outer surface material that forms an outer surface of the pile body and has water permeability, and a plurality of sandbag materials laminated inside the outer surface material, and the sandbag material has water permeability. A foundation structure characterized in that a sandbag of a predetermined size is packed with granular materials. 前記上部構造から前記複数の杭体までを含めた建物の全体重量と、前記基礎本体から前記重量調整層及び前記杭体までを含めた地中部の排土体積と、によって算出される密度（全体重量／排土体積）が略１．０ｔ／ｍ3〜１．５ｔ／ｍ3となるように前記重量調整層の比重が設定されていることを特徴とする請求項１に記載の基礎構造。 The density calculated by the total weight of the building including the upper structure to the plurality of pile bodies, and the earth removal volume including the foundation body to the weight adjustment layer and the pile bodies (the whole basic structure according to claim 1, wherein the weight / earth removal volume) the specific gravity of the weight adjustment layer so as to be substantially 1.0t / m 3 ~1.5t / m 3 is set. 前記重量調整層は、事後発泡性コンクリートから構成されるとともに、該重量調整層の比重が０．５〜１．０の範囲に設定されていることを特徴とする請求項１又は２に記載の基礎構造。   3. The weight adjusting layer according to claim 1, wherein the weight adjusting layer is composed of post-expandable concrete, and the specific gravity of the weight adjusting layer is set in a range of 0.5 to 1.0. Foundation structure. 前記基礎本体と前記重量調整層との間には、複数の土嚢材を積層して構成される透水層が設けられ、該透水層の下面に前記杭体の杭頭部が連続して設けられていることを特徴とする請求項１〜３のいずれか一項に記載の基礎構造。   Between the foundation main body and the weight adjustment layer, a water permeable layer configured by laminating a plurality of sandbag materials is provided, and a pile head of the pile body is continuously provided on a lower surface of the water permeable layer. The foundation structure according to any one of claims 1 to 3, wherein the foundation structure is provided. 請求項１〜４のいずれか一項に記載の基礎構造に係る基礎の構築方法であって、
前記杭体の寸法に応じて地盤を掘削し、掘削した掘削孔に前記杭体の外面材をセットし、セットした外面材に前記複数の土嚢材を投入し、該土嚢材を積層して前記杭体を構築し、
前記基礎本体及び前記重量調整層が構築される領域の地盤を掘削し、掘削して露出した前記杭体の杭頭部と一体的に前記重量調整層を構築し、構築した該重量調整層の上面部に前記杭体の外面材を接続してから、前記杭体及び前記重量調整層の上側に前記基礎本体を構築することを特徴とする基礎の構築方法。 It is the construction method of the foundation which concerns on the foundation structure as described in any one of Claims 1-4,
The ground is excavated according to the dimensions of the pile body, the outer surface material of the pile body is set in the excavated excavation hole, the plurality of sandbag materials are thrown into the set outer surface material, the sandbag materials are stacked, Build a pile,
Excavating the ground in the region where the foundation main body and the weight adjustment layer are constructed, constructing the weight adjustment layer integrally with the pile head of the pile body exposed by excavation, A foundation construction method, comprising: connecting an outer surface material of the pile body to an upper surface portion; and constructing the foundation body above the pile body and the weight adjustment layer. 前記重量調整層の上面部に前記杭体の外面材を接続した後に、前記杭体及び前記重量調整層の上側に複数の土嚢材を積層して透水層を形成してから、形成した該透水層の上側に前記基礎本体を構築することを特徴とする請求項５に記載の基礎の構築方法。   After connecting the outer surface material of the said pile body to the upper surface part of the said weight adjustment layer, after forming a water permeable layer by laminating | stacking a plurality of sandbag materials on the said pile body and the said weight adjustment layer, this water permeability formed The foundation construction method according to claim 5, wherein the foundation body is constructed on an upper side of a layer.
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