JPH09209372A - Base-isolation foundation and structure - Google Patents
Base-isolation foundation and structureInfo
- Publication number
- JPH09209372A JPH09209372A JP2140996A JP2140996A JPH09209372A JP H09209372 A JPH09209372 A JP H09209372A JP 2140996 A JP2140996 A JP 2140996A JP 2140996 A JP2140996 A JP 2140996A JP H09209372 A JPH09209372 A JP H09209372A
- Authority
- JP
- Japan
- Prior art keywords
- ground
- piles
- building
- soft
- seismic
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
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- Foundations (AREA)
- Buildings Adapted To Withstand Abnormal External Influences (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、杭で支持される構
造物に伝わる地震力を低減させる免震地盤及び免震構造
に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a base isolation structure and a base isolation structure for reducing seismic force transmitted to a structure supported by piles.
【０００２】[0002]
【従来の技術】建物の構造設計の分野では、地震力を抑
制又は制御して、地震力のエネルギーが建物に伝わらな
いようにする「免震」という考え方が導入されている。2. Description of the Related Art In the field of structural design of buildings, the concept of "seismic isolation" is introduced to suppress or control seismic force so that the energy of seismic force is not transmitted to the building.
【０００３】しかし、従来、免震といえば建物構造や建
物基礎の方に主眼が置かれ、建物を支持する地盤に着目
して「免震」を考えた例が見られない。Conventionally, however, seismic isolation is mainly focused on the building structure and the building foundation, and there is no example in which "seismic isolation" is considered by focusing on the ground supporting the building.
【０００４】一方、地盤に打ち込まれた杭に支持される
建物の場合、地盤によって増幅された地震動による建物
の慣性力に考慮して、杭の耐震設計を行い、また、建物
及び地盤の固有周期より十分長い周期を有する免震装置
を設置することで、建物の免震設計を行うようになって
いる。On the other hand, in the case of a building supported by piles driven into the ground, seismic design of the pile is performed in consideration of the inertial force of the building due to the ground motion amplified by the ground, and the natural period of the building and the ground The seismic isolation design of buildings is designed by installing seismic isolation devices with a sufficiently long period.
【０００５】しかし、軟弱地盤の場合、地盤の固有周期
が免震装置の周期に近づくため、免震効果が半減して、
建物に地震力が伝達されてしまう。However, in the case of soft ground, the natural period of the ground approaches the period of the seismic isolation device, so the seismic isolation effect is halved,
The seismic force is transmitted to the building.
【０００６】[0006]
【発明が解決しようとする課題】本発明は係る事実を考
慮し、地盤に打ち込まれた杭に支持された建物への地震
入力を低減させることを課題とする。SUMMARY OF THE INVENTION In consideration of such a fact, the present invention has an object to reduce seismic input to a building supported by piles driven into the ground.
【０００７】[0007]
【課題を解決するための手段】請求項１に記載の発明で
は、土中に打ち込まれた杭の頭部に構造物が支持されて
いる。この杭の周辺には軟弱体が構築され、この軟弱体
を取り囲むように硬質体が構築されている。According to the first aspect of the invention, the structure is supported by the head of the pile driven into the soil. A soft body is built around the pile, and a hard body is built so as to surround the soft body.
【０００８】このため、大きなマスとしての硬質体で杭
に伝わる地震力が遮断され、また、軟弱体が緩衝層とな
って、杭に作用する側土圧が低減される。また、軟弱体
によって杭の水平移動が拘束されないので、杭を介して
構造物に伝達される地震力が低減される。For this reason, the seismic force transmitted to the pile is blocked by the hard body as a large mass, and the soft body serves as a buffer layer to reduce the side earth pressure acting on the pile. Further, since the horizontal movement of the pile is not restricted by the soft body, the seismic force transmitted to the structure via the pile is reduced.
【０００９】請求項２に記載の発明では、硬質体を格子
枠として軟弱体を取り囲むことで、改良する地盤が最小
限で済み、また、軟弱体を隙間なく取り囲むことができ
る。According to the second aspect of the present invention, by surrounding the soft body by using the hard body as a lattice frame, the ground to be improved can be minimized, and the soft body can be surrounded without a gap.
【００１０】請求項３に記載の発明では、軟弱地盤を改
良することで免震地盤としている。すなわち、軟弱体を
構成するため、軟弱な地盤を改良の対象から外し、この
軟弱体の外周の軟弱地盤を固結することで、硬質体が構
成される。このため、施工コストの点で優れた免震地盤
とすることができる。According to the third aspect of the invention, the seismically isolated ground is obtained by improving the soft ground. That is, in order to form a soft body, the soft ground is removed from the object of improvement, and the soft ground on the outer periphery of the soft body is solidified to form the hard body. For this reason, it is possible to provide a seismic isolated ground that is excellent in terms of construction cost.
【００１１】請求項４に記載の発明では、軟弱体が柔軟
材に置き換えられている。この柔軟材の粘性、密度等を
調整することによって、杭に作用する側土圧を調整する
と共に、減衰力を付加することができる。In the fourth aspect of the invention, the soft body is replaced with a soft material. By adjusting the viscosity, density, etc. of this soft material, it is possible to adjust the side earth pressure acting on the pile and add a damping force.
【００１２】請求項５及び請求項６に記載の発明では、
免震手段としての積層ゴム及びダンパーが、杭に支持さ
れた構造物の下部と硬質体との間に介在されている。従
って、杭から構造物に入力した地震力は、免震手段によ
って減衰され、構造物から離れた硬質体及びその周辺に
逸散される。また、逆に、周辺に地盤から硬質体へ伝達
された地震力は、積層ゴム及びダンパーによって減衰さ
れ、構造物への伝達が低減される。According to the inventions of claims 5 and 6,
A laminated rubber and a damper as seismic isolation means are interposed between the lower portion of the structure supported by the pile and the hard body. Therefore, the seismic force input to the structure from the pile is attenuated by the seismic isolation means and diffused to the hard body separated from the structure and its periphery. On the contrary, the seismic force transmitted to the surroundings from the ground to the hard body is attenuated by the laminated rubber and the damper, and the transmission to the structure is reduced.
【００１３】[0013]
【発明の実施の形態】図１に示すように、本形態に係る
免震地盤は、杭１０に支持された建物１２の免震に用い
られている。BEST MODE FOR CARRYING OUT THE INVENTION As shown in FIG. 1, the seismic isolation ground according to this embodiment is used for seismic isolation of a building 12 supported by piles 10.
【００１４】杭１０は鋼管あるいはコンクリート杭等
で、先端が軟弱地盤１４から支持層１６（洪積層又は沖
積層）へ達するように打ち込まれている。杭１０の頭部
は、ＲＣのベーススラブ１８で連結されており、このベ
ーススラブ１８の上に建物１２が構築されている。The pile 10 is a steel pipe, a concrete pile, or the like, and is driven so that the tip thereof reaches the support layer 16 (dipping layer or alluvial layer) from the soft ground 14. The heads of the piles 10 are connected by an RC base slab 18, and the building 12 is constructed on the base slab 18.
【００１５】また、杭１０の頭部付近の軟弱地盤は排土
され、後述する地盤改良体２０とベーススラブ１８との
間に、免震装置２２が設置される空間が形成されてい
る。Further, the soft ground near the head of the pile 10 is discharged, and a space for installing a seismic isolation device 22 is formed between a ground improvement body 20 and a base slab 18 which will be described later.
【００１６】図２に示すように、杭１０が打ち込まれた
後、杭１０の周辺の軟弱地盤１４を平面視にて矩形状に
取り残して、地盤改良体２０が構築されている。As shown in FIG. 2, after the pile 10 is driven in, the soft ground 14 around the pile 10 is left in a rectangular shape in plan view to construct a ground improvement body 20.
【００１７】この地盤改良体２０は、軟弱地盤１４へ図
示しないアースオーガーを回転挿入し、同時にアースオ
ーガーの芯部に配置されたパイプからセメントミルクを
注入し、孔中の土とセメントミルクを混合したセメント
ソイル柱Ａの列によって構築される。In this ground improvement body 20, an earth auger (not shown) is rotationally inserted into the soft ground 14, and at the same time, cement milk is injected from a pipe arranged at the core of the earth auger to mix the soil in the hole with the cement milk. It is constructed by rows of cement soil pillars A.
【００１８】また、地盤改良体２０は、杭１０を全て囲
む表面積を有し、深さは、杭長及び建物の高さ等によっ
て決定されるが、本形態では約５ｍとされている。地盤
改良体２０の上には、ベースマット２４が敷かれ、地盤
改良体２０を一体となって挙動するようになっている。The ground improvement body 20 has a surface area that surrounds all the piles 10, and the depth is determined by the pile length, the height of the building, etc., but is about 5 m in this embodiment. A base mat 24 is laid on the ground improvement body 20 so that the ground improvement body 20 integrally behaves.
【００１９】ベースマット２４の上には、免震装置２２
が設置されている。この免震装置２２は、積層ゴムとダ
ンパーによって構成されている。積層ゴムは、薄い鉄板
とゴムシートを何層も重ねたもので、建物１２の荷重の
一部を負担すると共に、地震時に建物１２に生じる応答
加速度を小さくして、建物１２全体を水平方向にゆっく
りと移動させるようになっている。この水平変位を減少
させるために、ダンパーが配置されており、粘性体のせ
ん断抵抗あるいは鉛・鋼棒等の弾塑性抵抗力等によって
揺れを大幅に減衰させるようになっている。The seismic isolation device 22 is mounted on the base mat 24.
Is installed. The seismic isolation device 22 is composed of laminated rubber and a damper. The laminated rubber is a stack of thin iron plates and rubber sheets, and bears a part of the load of the building 12 and reduces the response acceleration generated in the building 12 during an earthquake to make the entire building 12 horizontal. It is designed to move slowly. In order to reduce this horizontal displacement, a damper is arranged so that the vibration is greatly damped by the shear resistance of the viscous body or the elasto-plastic resistance force of the lead / steel rod or the like.
【００２０】次に、本形態の作用を説明する。免震地盤
では、地盤改良体２０によって杭１０へ伝わる地震力が
吸収され、また、杭１０周辺の軟弱地盤１４が緩衝層と
なって、杭１０に作用する側土圧が低減される。また、
軟弱地盤１４であるため、杭１０の水平方向への変位が
拘束されず、杭１０を介して建物１２に伝達される地震
力が低減される。このように、本形態では、杭１０周辺
の軟弱地盤を改良するだけで、建物１２を免震構造とす
ることができる。Next, the operation of this embodiment will be described. In the base-isolated ground, the ground improvement body 20 absorbs the seismic force transmitted to the pile 10, and the soft ground 14 around the pile 10 serves as a buffer layer to reduce the side earth pressure acting on the pile 10. Also,
Since it is the soft ground 14, the displacement of the pile 10 in the horizontal direction is not restricted, and the seismic force transmitted to the building 12 via the pile 10 is reduced. As described above, in the present embodiment, the building 12 can have the seismic isolation structure only by improving the soft ground around the pile 10.
【００２１】また、積層ゴム及びダンパーによって、杭
１０から建物１２に入力した地震力は減衰され、周辺の
地盤から地盤改良体２０へ伝達された地震力は、積層ゴ
ム及びダンパーによって減衰され、建物１２への伝達が
低減される。Further, the laminated rubber and the damper attenuate the seismic force inputted from the pile 10 to the building 12, and the seismic force transmitted from the surrounding ground to the ground improvement body 20 is attenuated by the laminated rubber and the damper, Transmission to 12 is reduced.
【００２２】なお、本形態では、建物１２の下部全体を
地盤改良体２０としたが、図３に示すように、杭１０を
取り囲むようにして格子状に地盤改良体２８を構築して
もよい。In the present embodiment, the entire lower portion of the building 12 is the ground improvement body 20, but as shown in FIG. 3, the ground improvement body 28 may be constructed in a lattice shape so as to surround the piles 10. .
【００２３】また、杭１０の周辺の軟弱地盤を水等に置
き換えることによって、ダンパー効果を発揮させるよう
にすることもできる。さらに、建物１２が設置される地
盤が硬質である場合、逆に杭１０の周辺を軟弱にするよ
うにしてもよい。Further, by replacing the soft ground around the pile 10 with water or the like, the damper effect can be exhibited. Further, when the ground on which the building 12 is installed is hard, the periphery of the pile 10 may be softened.
【００２４】また、本形態では、新築される建物を対象
とした施工方法を説明したが、既存の建物であっても、
図４及び図５に示すように、斜めにオーガーを矢印方向
へ打ち込んで地盤改良用の薬液を注入して、地盤改良体
３０を構築してもよい。In the present embodiment, the construction method for a newly constructed building has been described, but even for an existing building,
As shown in FIGS. 4 and 5, the ground improvement body 30 may be constructed by driving an auger diagonally in the direction of the arrow and injecting a chemical solution for ground improvement.
【００２５】[0025]
【発明の効果】本発明は上記構成としたので、地盤に打
ち込まれた杭に支持された建物への地震入力を低減させ
ることができる。Since the present invention has the above-mentioned structure, it is possible to reduce the seismic input to the building supported by the piles driven into the ground.
【図１】本形態に係る免震地盤及び免震構造の断面図で
ある。FIG. 1 is a sectional view of a base-isolated ground and a base-isolated structure according to the present embodiment.
【図２】本形態に係る免震地盤の平断面図である。FIG. 2 is a plan sectional view of the seismic isolated ground according to the present embodiment.
【図３】変形例に係る免震地盤の平断面図である。FIG. 3 is a plan sectional view of a seismic isolated ground according to a modification.
【図４】他の変形例に係る免震地盤の断面図である。FIG. 4 is a cross-sectional view of seismic isolated ground according to another modification.
【図５】他の変形例に係る免震地盤の平断面図である。FIG. 5 is a plan sectional view of a seismic isolated ground according to another modification.
１４ 軟弱地盤（軟弱体） ２０ 地盤改良体（硬質体） ２２ 免震装置 ２８ 地盤改良体（格子枠） 14 Soft ground (soft body) 20 Ground improved body (hard body) 22 Seismic isolation device 28 Ground improved body (lattice frame)
Claims (6)
た杭の周辺に構築された軟弱体と、前記軟弱体を取り囲
むように構築された硬質体と、を有することを特徴とす
る免震地盤。1. A soft body constructed around a pile that supports a structure on a head and is driven into the soil, and a hard body constructed so as to surround the soft body. Seismically isolated ground.
子枠であることを特徴とする請求項１に記載の免震地
盤。2. The seismic isolated ground according to claim 1, wherein the hard body is a lattice frame surrounding the soft body.
が前記軟弱な地盤を固結改良したものであることを特徴
とする請求項１又は請求項２に記載の免震地盤。3. The seismic isolated ground according to claim 1, wherein the soft body is a soft ground, and the hard body is an improved consolidation of the soft ground.
とを特徴とする請求項３に記載の免震地盤。4. The seismic isolated ground according to claim 3, wherein the soft body is replaced with a soft material.
る杭と、前記杭の周辺に構築された軟弱体と、前記軟弱
体を取り囲むように構築された硬質体と、前記硬質体と
前記構造物の下部との間に介在された免震手段と、を有
することを特徴とする免震構造。5. A pile that is driven into the soil to support a structure on the head, a soft body constructed around the pile, a hard body constructed so as to surround the soft body, and the hard body. And a seismic isolation means interposed between the lower part of the structure and the seismic isolation structure.
で構成されたことを特徴とする請求項５に記載の免震構
造。6. The seismic isolation structure according to claim 5, wherein the seismic isolation means includes a laminated rubber and a damper.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2140996A JPH09209372A (en) | 1996-02-07 | 1996-02-07 | Base-isolation foundation and structure |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2140996A JPH09209372A (en) | 1996-02-07 | 1996-02-07 | Base-isolation foundation and structure |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH09209372A true JPH09209372A (en) | 1997-08-12 |
Family
ID=12054240
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2140996A Pending JPH09209372A (en) | 1996-02-07 | 1996-02-07 | Base-isolation foundation and structure |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH09209372A (en) |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2003096796A (en) * | 2001-09-21 | 2003-04-03 | Tenox Corp | Foundation formation of structure |
| JP2005016292A (en) * | 2003-05-30 | 2005-01-20 | Toda Constr Co Ltd | Combined footing of pile and diaphragm wall |
| JP2007009421A (en) * | 2005-06-28 | 2007-01-18 | Shimizu Corp | Foundation structure of structure |
| JP2008038511A (en) * | 2006-08-08 | 2008-02-21 | Taisei Corp | Pile foundation reinforcing structure |
| JP2010270565A (en) * | 2009-05-25 | 2010-12-02 | Shimizu Corp | Liquefaction countermeasure structure for structure and liquefaction countermeasure method for structure |
| JP2015010435A (en) * | 2013-07-01 | 2015-01-19 | 株式会社竹中工務店 | Foundation structure and design method for the same |
| JP2020016038A (en) * | 2018-07-24 | 2020-01-30 | 積水化学工業株式会社 | Foundation structure for ground improvement |
-
1996
- 1996-02-07 JP JP2140996A patent/JPH09209372A/en active Pending
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2003096796A (en) * | 2001-09-21 | 2003-04-03 | Tenox Corp | Foundation formation of structure |
| JP4707287B2 (en) * | 2001-09-21 | 2011-06-22 | 株式会社テノックス | Basic structure of the structure |
| JP2005016292A (en) * | 2003-05-30 | 2005-01-20 | Toda Constr Co Ltd | Combined footing of pile and diaphragm wall |
| JP2007009421A (en) * | 2005-06-28 | 2007-01-18 | Shimizu Corp | Foundation structure of structure |
| JP2008038511A (en) * | 2006-08-08 | 2008-02-21 | Taisei Corp | Pile foundation reinforcing structure |
| JP2010270565A (en) * | 2009-05-25 | 2010-12-02 | Shimizu Corp | Liquefaction countermeasure structure for structure and liquefaction countermeasure method for structure |
| JP2015010435A (en) * | 2013-07-01 | 2015-01-19 | 株式会社竹中工務店 | Foundation structure and design method for the same |
| JP2020016038A (en) * | 2018-07-24 | 2020-01-30 | 積水化学工業株式会社 | Foundation structure for ground improvement |
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