JP2005105602A - Counter measure structure for liquefaction - Google Patents

Counter measure structure for liquefaction Download PDF

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JP2005105602A
JP2005105602A JP2003338419A JP2003338419A JP2005105602A JP 2005105602 A JP2005105602 A JP 2005105602A JP 2003338419 A JP2003338419 A JP 2003338419A JP 2003338419 A JP2003338419 A JP 2003338419A JP 2005105602 A JP2005105602 A JP 2005105602A
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ground
liquefaction
ground improvement
improvement body
layer
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Hiroyuki Hotta
洋之 堀田
Yutaka Katsura
豊 桂
Yasuhiro Shamoto
康広 社本
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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 provide a counter measure structure for liquefaction capable of largely reducing construction cost and a construction period for counter measures for liquefaction, by stably supporting the structure, even if the ground is liquefied. <P>SOLUTION: This structure 4 is constructed on the ground 1 composed of a liquefaction layer 2 and an unliquefied layer 3 under the liquefaction layer 2. A ground improver 5 having the predetermined width thickness is formed up to the unliequefied layer 3 from a foundation lower end surface of the structure 4 on the outer periphery of the structure 4. An area surrounded by the ground improver 5 is a ground unimproved part 6. The ground improver 5 is not necessary to be a continuous body in a plan view, and the composite ground composed of the ground improver 5 of the outer periphery of the structure 4 and the ground unimproved part 6 surrounded by the ground improver 5, preferably has a predetermined equivalent shearing elastic modulus, and the ground improver 5 may be formed at a specific separate interval on the outer periphery of the structure 4. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

本発明は、液状化する可能性のある液状化層上に構築される構造物の基礎地盤の液状化対策構造に関する。   The present invention relates to a liquefaction countermeasure structure for a foundation ground of a structure constructed on a liquefied layer that may be liquefied.

支持杭を有しない中低層の建築物やタンク等の構造物が、地震時に液状化する可能性のある砂質土層（以下、液状化層と呼ぶ。）上に構築されている場合、液状化による液状化層の体積変化により、当該構造物が沈下し、不具合が発生するおそれがある。
そこで、従来より、構造物下方の液状化層を地盤改良し、液状化そのものの発生を防止する対策が採られているが、液状化を完全に抑えるのは困難な場合もある。特に、既設構造物の場合には、既設構造物の外周から薬液注入を行うなど地盤改良の方法も限られ、構造物の規模や液状化層厚が大きくなるに伴い、地盤改良に掛かる工費や工期は膨大なものとなる。
これに対して、特許文献１では、既設構造物外周部の直下の液状化層のみを、非液状化層に至るまで地盤改良することにより固化柱状体を形成し、当該固化柱状体によって前記既設構造物を支持する発明が提案されている。
特開平８−１２８０５４号公報 （第２−３頁、第４図） When structures such as low-rise buildings and tanks that do not have support piles are constructed on sandy soil layers (hereinafter referred to as liquefied layers) that may liquefy during an earthquake, Due to the change in the volume of the liquefied layer due to liquefaction, the structure may sink and a problem may occur.
Therefore, conventionally, measures have been taken to improve the ground of the liquefied layer below the structure and prevent the occurrence of liquefaction itself, but it may be difficult to completely suppress liquefaction. In particular, in the case of existing structures, there are limited ground improvement methods such as injecting chemicals from the outer periphery of the existing structure, and as the scale of the structure and the liquefied layer thickness increase, the construction cost and The construction period will be enormous.
On the other hand, in Patent Document 1, a solidified columnar body is formed by improving only the liquefied layer directly below the outer peripheral portion of the existing structure until reaching the non-liquefied layer, and the solidified columnar body forms the solidified columnar body. Inventions that support structures have been proposed.
JP-A-8-128054 (page 2-3, FIG. 4)

しかしながら、特許文献１に記載の発明は、固化柱状体によって既設構造物を支持するため、当該既設構造物下の液状化層も部分的に地盤改良する必要がある。そのため、作業に困難を伴う場合があり、液状化層が厚くなると、地盤改良に掛かる工費や工期は大きなものとなる。
本発明は、上述する問題点に鑑みてなされたもので、地盤が液状化しても、構造物を安定的に支持できるとともに、液状化対策のための工費および工期を大幅に削減することができる構造物の基礎地盤の液状化対策構造を提供することを目的とする。 However, since the invention described in Patent Document 1 supports the existing structure by the solidified columnar body, it is necessary to partially improve the ground of the liquefied layer under the existing structure. Therefore, the work may be difficult, and when the liquefied layer becomes thick, the construction cost and construction period for ground improvement become large.
The present invention has been made in view of the above-described problems, and can stably support a structure even when the ground is liquefied, and can greatly reduce the construction cost and the construction period for countermeasures against liquefaction. It aims at providing the liquefaction countermeasure structure of the foundation ground of a structure.

上記目的を達成するため、本発明に係る構造物の基礎地盤の液状化対策構造では、液状化する可能性のある液状化層上に構築される構造物の基礎地盤の液状化対策構造であって、平面視で前記構造物を所定の幅厚をもって囲繞する地盤改良体が、鉛直方向に少なくとも前記構造物の基礎下端面から非液状化層まで形成されていることを特徴とする。
本発明は、固化柱状体によって構造物を支持するのではなく、構造物の外周に地盤改良体からなる高剛性の壁を構築し、当該壁によって、当該壁に囲まれた地盤未改良部を拘束することにより、地盤が液状化しても、構造物を安定的に支持するものである。
前記地盤改良体に囲まれた地盤未改良部は、せん断弾性係数の高い周囲の前記地盤改良体に拘束されて一体となって挙動するため、地震時に発生するせん断ひずみは小さく、液状化に至ることはない。多少間隙水圧が上昇した場合でも、地震後に生ずる体積ひずみは地震時に生じた最大せん断ひずみの大きさに依存するため、前記地盤未改良部に生じる沈下は微小なものとなる。
ここで、前記地盤改良体の幅厚は、前記地盤改良体と前記地盤未改良部とからなる複合地盤が所定の等価せん断弾性係数を有するように設定しなければならない。即ち、地盤条件に応じて、構造物の基礎面積に対する前記地盤改良体の面積（前記地盤改良体の幅厚が関係する。）の割合を示す地盤改良率および前記地盤改良体のせん断弾性係数を設定し、前記複合地盤が所定の等価せん断弾性係数を有するようにしなければならない。 In order to achieve the above-mentioned object, the structure liquefaction countermeasure structure of the foundation ground of the structure according to the present invention is a liquefaction countermeasure structure of the foundation foundation of a structure constructed on a liquefied layer that may be liquefied. The ground improvement body that surrounds the structure with a predetermined width and thickness in plan view is formed in a vertical direction from at least the base lower end surface of the structure to the non-liquefied layer.
The present invention does not support the structure by the solidified columnar body, but constructs a high-rigidity wall made of a ground improvement body on the outer periphery of the structure, and by the wall, the ground unimproved portion surrounded by the wall is formed. By restraining, the structure is stably supported even when the ground is liquefied.
The unimproved portion of the ground surrounded by the ground improvement body behaves integrally with the surrounding ground improvement body having a high shear elastic modulus, so that the shear strain generated during an earthquake is small and liquefies. There is nothing. Even if the pore water pressure increases to some extent, the volume strain generated after the earthquake depends on the magnitude of the maximum shear strain generated at the time of the earthquake, so that the subsidence generated in the unimproved portion of the ground is very small.
Here, the width and thickness of the ground improvement body must be set so that the composite ground consisting of the ground improvement body and the ground unimproved portion has a predetermined equivalent shear modulus. That is, according to the ground conditions, the ground improvement rate indicating the ratio of the area of the ground improvement body to the basic area of the structure (the width and thickness of the ground improvement body is related) and the shear elastic modulus of the ground improvement body It must be set so that the composite ground has a predetermined equivalent shear modulus.

本発明では、構造物の外周に所定の幅厚を有する地盤改良体を、鉛直方向に少なくとも構造物の基礎下端面から非液状化層まで形成することにより、地盤が液状化しても、構造物を安定的に支持できるとともに、液状化対策のための工費および工期を大幅に削減することができる。   In the present invention, even if the ground is liquefied, the ground improvement body having a predetermined width and thickness on the outer periphery of the structure is formed in the vertical direction from at least the base lower end surface of the structure to the non-liquefied layer. Can be supported stably, and the construction cost and construction period for liquefaction measures can be greatly reduced.

また、本発明に係る構造物の基礎地盤の液状化対策構造では、前記地盤改良体が、平面視で不連続であってもよい。
構造物の外周に形成される前記地盤改良体は、平面視で必ずしも連続体である必要はなく、前記地盤改良体と地盤未改良部とからなる複合地盤が所定の等価せん断弾性係数を有していれば、構造物の外周に沿って一定の離間間隔をおいて前記地盤改良体が形成されていてもよい。 In the liquefaction countermeasure structure for a foundation ground of a structure according to the present invention, the ground improvement body may be discontinuous in plan view.
The ground improvement body formed on the outer periphery of the structure does not necessarily need to be a continuous body in plan view, and the composite ground composed of the ground improvement body and the ground unmodified portion has a predetermined equivalent shear modulus. If it is, the said ground improvement body may be formed in the outer periphery of a structure at fixed spacing intervals.

また、本発明に係る構造物の基礎地盤の液状化対策構造では、前記地盤改良体によって囲まれた領域に、前記地盤改良体よりも低いせん断弾性係数を有する地盤改良体が形成されていてもよい。
本発明では、構造物の外周に形成された前記地盤改良体によって囲まれた領域に、前記地盤改良体よりも低いせん断弾性係数を有する地盤改良体が形成されることにより、前記領域における液状化の発生を完全に防止することができる。 In the liquefaction countermeasure structure for the foundation ground of the structure according to the present invention, even if a ground improvement body having a lower shear elastic modulus than the ground improvement body is formed in a region surrounded by the ground improvement body. Good.
In the present invention, a ground improvement body having a lower shear elastic modulus than the ground improvement body is formed in a region surrounded by the ground improvement body formed on the outer periphery of the structure, thereby liquefaction in the region. Can be completely prevented.

本発明によれば、構造物の外周に所定の幅厚を有する地盤改良体を、鉛直方向に少なくとも構造物の基礎下端面から非液状化層まで形成することにより、地盤が液状化しても、構造物を安定的に支持できるとともに、液状化対策のための工費および工期を大幅に削減することができる構造物の基礎地盤の液状化対策構造を実現することができる。   According to the present invention, by forming a ground improvement body having a predetermined width and thickness on the outer periphery of the structure in the vertical direction from at least the foundation bottom surface of the structure to the non-liquefiable layer, It is possible to realize a liquefaction countermeasure structure for the foundation ground of the structure that can stably support the structure and can significantly reduce the construction cost and the construction period for the liquefaction countermeasure.

以下、本発明に係る構造物の基礎地盤の液状化対策構造の実施形態について、図面に基いて説明する。
図１は、本発明に係る構造物の基礎地盤の液状化対策構造の第一の実施形態を示す立断面図である。また、図２は、本発明の第一の実施形態を示す平断面図である。
図１に示すように、本実施形態による構造物の基礎地盤の液状化対策構造では、液状化層２と液状化層２下の非液状化層３とからなる地盤１上に、構造物４が構築されている。そして、構造物４の外周には、所定の幅厚を有する地盤改良体５が、構造物４基礎下端面から非液状化層３まで形成されている。一方、地盤改良体５に囲まれた領域は地盤未改良部６である。
地盤改良体５は、平面視で、必ずしも図２に示すような連続体である必要はない。構造物４の外周の地盤改良体５と地盤改良体５に囲まれた地盤未改良部６とからなる複合地盤が所定の等価せん断弾性係数を有していればよく、図３に示すように、構造物４の外周に沿って一定の離間間隔７をおいて地盤改良体５が形成されていてもよい。
ここで、地盤改良体５は、地盤改良を行う際に一般的に用いられるセメント系の固化材料又は液状化対策として用いられる水ガラス系薬液注入材料等により構成されている。地盤改良体５は平面視で構造物４の外側にあるため、使用中の構造物４であっても施工が可能である。 Hereinafter, an embodiment of a liquefaction countermeasure structure for a foundation ground of a structure according to the present invention will be described based on the drawings.
FIG. 1 is an elevational cross-sectional view showing a first embodiment of a liquefaction countermeasure structure for a foundation ground of a structure according to the present invention. FIG. 2 is a plan sectional view showing the first embodiment of the present invention.
As shown in FIG. 1, in the liquefaction countermeasure structure of the foundation ground of the structure according to the present embodiment, the structure 4 is formed on the ground 1 composed of the liquefied layer 2 and the non-liquefied layer 3 below the liquefied layer 2. Has been built. And on the outer periphery of the structure 4, a ground improvement body 5 having a predetermined width and thickness is formed from the bottom end surface of the structure 4 to the non-liquefied layer 3. On the other hand, the area surrounded by the ground improvement body 5 is the ground unimproved portion 6.
The ground improvement body 5 does not necessarily need to be a continuous body as shown in FIG. The composite ground consisting of the ground improvement body 5 on the outer periphery of the structure 4 and the ground unimproved portion 6 surrounded by the ground improvement body 5 only needs to have a predetermined equivalent shear modulus, as shown in FIG. The ground improvement body 5 may be formed with a certain spacing 7 along the outer periphery of the structure 4.
Here, the ground improvement body 5 is composed of a cement-based solidification material generally used for ground improvement or a water glass-based chemical injection material used as a liquefaction countermeasure. Since the ground improvement body 5 is outside the structure 4 in a plan view, even the structure 4 in use can be constructed.

地盤改良体５に囲まれた地盤未改良部６は、せん断弾性係数の高い周囲の地盤改良体５に拘束されて一体となって挙動するため、地震時に発生するせん断ひずみは小さく、液状化に至ることはない。多少間隙水圧が上昇した場合でも、地震後に生ずる体積ひずみは地震時に生じた最大せん断ひずみの大きさに依存するため、地盤未改良部６に生じる沈下は微小なものとなる。
地盤改良体５の幅厚は、地盤改良体５と地盤未改良部６とからなる複合地盤が所定の等価せん断弾性係数を有するように設定しなければならない。即ち、地盤条件に応じて、地盤改良率および地盤改良体５のせん断弾性係数を設定し、前記複合地盤が所定の等価せん断弾性係数を有するようにしなければならない。 Since the ground unimproved portion 6 surrounded by the ground improvement body 5 is restrained by the surrounding ground improvement body 5 having a high shear elastic modulus and behaves as one body, the shear strain generated at the time of the earthquake is small and liquefaction occurs. It will not reach. Even if the pore water pressure increases to some extent, the volume strain generated after the earthquake depends on the magnitude of the maximum shear strain generated at the time of the earthquake, so the subsidence generated in the unimproved portion 6 of the ground is very small.
The width and thickness of the ground improvement body 5 must be set so that the composite ground composed of the ground improvement body 5 and the ground unimproved portion 6 has a predetermined equivalent shear modulus. That is, according to the ground conditions, the ground improvement rate and the shear elastic modulus of the ground improvement body 5 must be set so that the composite ground has a predetermined equivalent shear elastic modulus.

第一の実施形態による構造物の基礎地盤の液状化対策構造では、構造物４の外周に所定の幅厚を有する地盤改良体５を、鉛直方向に少なくとも構造物４の基礎下端面から非液状化層３まで形成することにより、地盤１が液状化しても、構造物４を安定的に支持できるとともに、液状化対策のための工費および工期を大幅に削減することができる。   In the liquefaction countermeasure structure of the foundation ground of the structure according to the first embodiment, the ground improvement body 5 having a predetermined width and thickness on the outer periphery of the structure 4 is non-liquid at least from the bottom lower end surface of the structure 4 in the vertical direction. By forming up to the liquefied layer 3, even if the ground 1 is liquefied, the structure 4 can be stably supported, and the construction cost and construction period for liquefaction countermeasures can be greatly reduced.

図４乃至６は、本発明に係る構造物の基礎地盤の液状化対策構造の第二乃至第四の実施形態を示す立断面図である。
本発明では、図４に示すように、構造物４と構造物４外周の地盤改良体１５とを離間して設けてもよいし、図５や図６のように、地盤改良体２５が地表面から非液状化層３まで形成されていてもよいし、地盤改良体３５が構造物４の基礎下端面から非液状化層３内まで形成されていてもよい。要するに、構造物４下の地盤未改良部６、１６、２６、３６が、地盤改良体５、１５、２５、３５によって拘束され、地震時に、地盤改良体５、１５、２５、３５と一体となって挙動すればよいのである。 FIGS. 4 to 6 are elevation sectional views showing second to fourth embodiments of the liquefaction countermeasure structure for the foundation ground of the structure according to the present invention.
In the present invention, as shown in FIG. 4, the structure 4 and the ground improvement body 15 on the outer periphery of the structure 4 may be provided apart from each other, or the ground improvement body 25 may be provided as shown in FIGS. The surface to the non-liquefied layer 3 may be formed, or the ground improvement body 35 may be formed from the base lower end surface of the structure 4 to the non-liquefied layer 3. In short, the ground unimproved portions 6, 16, 26, 36 under the structure 4 are restrained by the ground improvement bodies 5, 15, 25, 35, and are integrated with the ground improvement bodies 5, 15, 25, 35 at the time of the earthquake. Just behave.

図７は、本発明に係る構造物の基礎地盤の液状化対策構造の第五の実施形態を示す立断面図である。
図７に示すように、本実施形態による構造物の基礎地盤の液状化対策構造では、構造物４の外周に形成された第一地盤改良体４５によって囲まれた領域に、第一地盤改良体４５よりも低いせん断弾性係数を有する第二地盤改良体４６が形成されている。
ここで、第一地盤改良体４５はセメント系の固化材料によって構成され、第二地盤改良体４６は水ガラス系薬液注入材料により構成されている。 FIG. 7 is an elevational sectional view showing a fifth embodiment of the liquefaction countermeasure structure for the foundation ground of the structure according to the present invention.
As shown in FIG. 7, in the liquefaction countermeasure structure for the foundation ground of the structure according to the present embodiment, the first ground improvement body is located in a region surrounded by the first ground improvement body 45 formed on the outer periphery of the structure 4. A second ground improvement body 46 having a shear elastic modulus lower than 45 is formed.
Here, the 1st ground improvement body 45 is comprised with the cement-type solidification material, and the 2nd ground improvement body 46 is comprised with the water glass type chemical | medical solution injection material.

第二の実施形態による構造物の基礎地盤の液状化対策構造では、構造物４の外周部の直下に形成された第一地盤改良体４５によって囲まれた領域に、第一地盤改良体４５よりも低いせん断弾性係数を有する第二地盤改良体４６が形成されることにより、前記領域における液状化の発生を完全に防止することができる。   In the liquefaction countermeasure structure for the foundation ground of the structure according to the second embodiment, the first ground improvement body 45 has a region surrounded by the first ground improvement body 45 formed immediately below the outer peripheral portion of the structure 4. By forming the second ground improvement body 46 having a low shear elastic modulus, the occurrence of liquefaction in the region can be completely prevented.

次に、液状化後の構造物４の沈下量の計算方法について説明する。なお、液状化後の構造物４の沈下量を精度良く行える方法であれば、本方法に限るものではない。
液状化後の構造物４の沈下量ＤＳは（１）式により求めることができる。 Next, a method for calculating the amount of settlement of the structure 4 after liquefaction will be described. Note that the method is not limited to this method as long as the amount of settlement of the structure 4 after liquefaction can be accurately performed.
Subsidence D S of the structure 4 after liquefaction can be obtained by (1).

Figure 2005105602
Figure 2005105602

ここで、残留体積ひずみ（εｖｒ）ｍａｘは、液状化前後の砂要素の体積変化量を液状化前の砂要素の体積で除したものであり、（２）式で表すことができる。 Here, the residual volume strain (ε vr ) max is obtained by dividing the volume change of the sand element before and after liquefaction by the volume of the sand element before liquefaction, and can be expressed by the equation (2).

Figure 2005105602
Figure 2005105602

（２）式における真の最小間隙比ｅｍｉｎ ＊は（３）式で表される。 The true minimum gap ratio e min * in equation (2) is expressed by equation (3).

Figure 2005105602
Figure 2005105602

砂の最大間隙比ｅｍａｘと砂の最小間隙比ｅｍｉｎは、最小・最大密度試験により求めることが望ましいが、経験的には細粒分含有率Ｆｃより以下の式を用いて求めることができる。 The maximum sand gap e max and the minimum sand sand ratio e min are preferably determined by a minimum / maximum density test, but empirically, the following formula is used to determine the fine grain content F c. it can.

Figure 2005105602
Figure 2005105602
Figure 2005105602
Figure 2005105602

また、液状化前の砂の間隙比ｅ０は、砂の最大間隙比ｅｍａｘと砂の最小間隙比ｅｍｉｎを用いて（６）式で表される。 Further, the sand gap ratio e 0 before liquefaction is expressed by equation (6) using the maximum sand gap ratio e max and the minimum sand gap ratio e min .

Figure 2005105602
Figure 2005105602

砂の相対密度Ｄｒは、現位置の砂の密度より求められるが、経験的には地盤の補正Ｎ値Ｎａを用いて（７）式から計算できる。 The relative density D r of sand is obtained from the density of the current position sand, is empirically be calculated from using the correction N value N a of the ground (7).

Figure 2005105602
Figure 2005105602
Figure 2005105602
Figure 2005105602

ここに、細粒分含有率に応じた補正Ｎ値増分ΔＮｆは、図８の補正Ｎ値増分と細粒分含有率との関係を示すグラフより求めることができる。 Here, the corrected N value increment ΔN f corresponding to the fine grain content can be obtained from the graph showing the relationship between the corrected N value increment and the fine grain content in FIG.

さて、本発明では、構造物４の支持地盤が、地盤改良体５、１５、２５、３５と地盤未改良部６、１６、２６、３６とからなる複合地盤、あるいは第一地盤改良体４５と第二地盤改良体４６とからなる複合地盤であるため、（１）式により液状化後の沈下量を求めるに際し、複合地盤の地震時最大せん断ひずみγｍａｘ’を用いる必要がある。
複合地盤の地震時最大せん断ひずみγｍａｘ’は（９）式で示される。 In the present invention, the supporting ground of the structure 4 is a composite ground composed of the ground improvement bodies 5, 15, 25, 35 and the ground unimproved portions 6, 16, 26, 36, or the first ground improvement body 45. Since it is a composite ground composed of the second ground improvement body 46, it is necessary to use the maximum shear strain γ max ′ during earthquake of the composite ground when calculating the subsidence amount after liquefaction by the equation (1).
The maximum shear strain γ max ′ during earthquake of the composite ground is expressed by equation (9).

Figure 2005105602
Figure 2005105602

（９）式中の地震時の最大せん断応力τｍａｘは（１０）式より、また、等価せん断弾性係数Ｇ’は（１１）式より、それぞれ求めることができる。 In equation (9), the maximum shear stress τ max during an earthquake can be obtained from equation (10), and the equivalent shear elastic modulus G ′ can be obtained from equation (11).

Figure 2005105602
Figure 2005105602
Figure 2005105602
Figure 2005105602

以上、本発明に係る構造物の基礎地盤の液状化対策構造の実施形態について説明したが、本発明は上記の実施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。例えば、上記の実施形態では既設構造物を対象にしているが、新たに構造物を建設する場合には、構造物の建設に先立って基礎地盤の地盤改良を行うことにより、構造物の自重による即時沈下量を低減することができる。   As mentioned above, although embodiment of the liquefaction countermeasure structure of the foundation ground of the structure based on this invention was described, this invention is not limited to said embodiment, It can change suitably in the range which does not deviate from the meaning. is there. For example, in the above embodiment, an existing structure is targeted. However, when a new structure is to be constructed, the ground of the foundation ground is improved prior to the construction of the structure. The amount of immediate settlement can be reduced.

本発明の第一の実施形態を示す立断面図である。It is an elevation sectional view showing a first embodiment of the present invention. 本発明の第一の実施形態を示す平断面図である。It is a plane sectional view showing a first embodiment of the present invention. 本発明の第一の実施形態を示す平断面図である。It is a plane sectional view showing a first embodiment of the present invention. 本発明の第二の実施形態を示す立断面図である。It is a sectional elevation showing a second embodiment of the present invention. 本発明の第三の実施形態を示す立断面図である。It is an elevation sectional view showing a third embodiment of the present invention. 本発明の第四の実施形態を示す立断面図である。It is a sectional elevation showing a fourth embodiment of the present invention. 本発明の第五の実施形態を示す立断面図である。It is a sectional elevation showing the fifth embodiment of the present invention. 補正Ｎ値増分と細粒分含有率との関係を示すグラフである。It is a graph which shows the relationship between correction | amendment N value increment and fine grain content rate.

符号の説明Explanation of symbols

１ 地盤
２ 液状化層
３ 非液状化層
４ 構造物
５、１５、２５、３５ 地盤改良体
６、１６、２６、３６ 地盤未改良部
７ 離間間隔
４５ 第一地盤改良体
４６ 第二地盤改良体 DESCRIPTION OF SYMBOLS 1 Ground 2 Liquefaction layer 3 Non-liquefaction layer 4 Structure 5, 15, 25, 35 Ground improvement body 6, 16, 26, 36 Ground unimproved part 7 Spacing space 45 First ground improvement body 46 Second ground improvement body

Claims (3)

液状化する可能性のある液状化層上に構築される構造物の基礎地盤の液状化対策構造であって、
平面視で前記構造物を所定の幅厚をもって囲繞する地盤改良体が、鉛直方向に少なくとも前記構造物の基礎下端面から非液状化層まで形成されていることを特徴とする構造物の基礎地盤の液状化対策構造。 A liquefaction countermeasure structure for the foundation ground of a structure built on a liquefiable layer that may liquefy,
The foundation ground of the structure, wherein the ground improvement body surrounding the structure with a predetermined width and thickness in a plan view is formed in the vertical direction from at least the foundation bottom surface of the structure to the non-liquefaction layer Liquefaction countermeasure structure. 前記地盤改良体が、平面視で不連続であることを特徴とする請求項１に記載の構造物の基礎地盤の液状化対策構造。   The structure according to claim 1, wherein the ground improvement body is discontinuous in plan view. 前記地盤改良体によって囲まれた領域に、前記地盤改良体よりも低いせん断弾性係数を有する地盤改良体が形成されていることを特徴とする請求項１又は２に記載の構造物の基礎地盤の液状化対策構造。   The ground improvement body according to claim 1 or 2, wherein a ground improvement body having a lower shear elastic modulus than that of the ground improvement body is formed in a region surrounded by the ground improvement body. Liquefaction countermeasure structure.
JP2003338419A 2003-09-29 2003-09-29 Counter measure structure for liquefaction Withdrawn JP2005105602A (en)

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Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2010133204A (en) * 2008-12-08 2010-06-17 Shimizu Corp Method for simply evaluating liquefaction strength of partially-improved ground, and method for simply evaluating deformation of the partially-improved ground
JP2011007031A (en) * 2009-05-25 2011-01-13 Shimizu Corp Structure and construction method for countermeasure against liquefaction
JP2011127417A (en) * 2009-11-17 2011-06-30 Port & Airport Research Institute Liquefaction countermeasure structure
JP2014214509A (en) * 2013-04-26 2014-11-17 大成建設株式会社 Liquefaction countermeasure structure of foundation by structure load
JP2019065629A (en) * 2017-10-03 2019-04-25 株式会社竹中工務店 Support structure for structural article
JP7423439B2 (en) 2020-06-23 2024-01-29 清水建設株式会社 Ground water stop method

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2010133204A (en) * 2008-12-08 2010-06-17 Shimizu Corp Method for simply evaluating liquefaction strength of partially-improved ground, and method for simply evaluating deformation of the partially-improved ground
JP2011007031A (en) * 2009-05-25 2011-01-13 Shimizu Corp Structure and construction method for countermeasure against liquefaction
JP2011127417A (en) * 2009-11-17 2011-06-30 Port & Airport Research Institute Liquefaction countermeasure structure
JP2014214509A (en) * 2013-04-26 2014-11-17 大成建設株式会社 Liquefaction countermeasure structure of foundation by structure load
JP2019065629A (en) * 2017-10-03 2019-04-25 株式会社竹中工務店 Support structure for structural article
JP7048013B2 (en) 2017-10-03 2022-04-05 株式会社竹中工務店 Support structure of structure
JP7423439B2 (en) 2020-06-23 2024-01-29 清水建設株式会社 Ground water stop method

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