JP2010112078A - Ground improving body and construction method of ground improving body - Google Patents

Ground improving body and construction method of ground improving body Download PDF

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JP2010112078A
JP2010112078A JP2008285793A JP2008285793A JP2010112078A JP 2010112078 A JP2010112078 A JP 2010112078A JP 2008285793 A JP2008285793 A JP 2008285793A JP 2008285793 A JP2008285793 A JP 2008285793A JP 2010112078 A JP2010112078 A JP 2010112078A
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improvement body
solidification
constructed
ground
ground improvement
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JP5206333B2 (en
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Shunichi Higuchi
俊一 樋口
Kiyoshi Sato
清 佐藤
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Obayashi Corp
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Abstract

<P>PROBLEM TO BE SOLVED: To reduce time, labor and cost required for constructing a ground improving body by reducing the volume of a solidification improving body. <P>SOLUTION: The ground improving body includes the solidification improving body 2 constructed in a soft layer 21 where a structure 10 is constructed, in a state of surrounding the structure 10, and steel members 5 provided on at least one of a structure side surface 3 of the solidification improving body 2 and a surface 4 opposite to the structure to contact the surface 3, 4 or to have a space and driven so that the lower ends reach a support layer 22 below the soft layer 21. Since the steel members 5 can resist sliding and rotating resistance of the soil improving body, the same degree of strength as what is composed of only the solidification improving body can be obtained even if reducing the depth and volume of the solidification improving body 2. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

本発明は、地盤改良体及び地盤改良体の構築方法に関し、特に、軟弱地盤に構築された構造物の地中構造部分を耐震補強するのに有効な地盤改良体及び地盤改良体の構築方法に関する。   The present invention relates to a ground improvement body and a method for constructing a ground improvement body, and more particularly to a ground improvement body effective for seismic reinforcement of an underground structure portion of a structure constructed on soft ground and a method for constructing a ground improvement body. .

一般に、軟弱地盤に構築されている構造物の基礎、杭等の地中構造部分を耐震補強する場合、図５に示すように、軟弱地盤２０の軟弱層２１に構造物１０の地中構造部分１１を囲むように固化系の地盤改良体１５を構築し、この地盤改良体１５の下端を軟弱層２１の下方の堅固な支持層２２に根入れさせることにより、構造物１０の地中構造部分１１の周囲の軟弱地盤２０を改良し、構造物１０の地中構造部分１１に耐震補強を施している。   In general, when an underground structure portion such as a foundation or a pile of a structure built on a soft ground is seismically reinforced, an underground structure portion of the structure 10 is formed on a soft layer 21 of the soft ground 20 as shown in FIG. 11, a solidified ground improvement body 15 is constructed so as to surround 11, and the lower end of the ground improvement body 15 is rooted in a solid support layer 22 below the soft layer 21, so that an underground structure portion of the structure 10 is obtained. The soft ground 20 around 11 is improved, and the underground structural portion 11 of the structure 10 is subjected to seismic reinforcement.

この種の耐震補強方法の一例が特許文献１に記載されている。この耐震補強方法は、構造物が構築されている軟弱地盤の砂層（軟弱層）に攪拌機を貫入させ、セメント系固化材を圧送しながら固化材と砂層の砂等とを攪拌混合することにより、構造物を囲んだ状態で固化系の地盤改良体である固結体を構築し、この固結体の下端を砂層の下方の堅固な粘性層（支持層）に根入れさせることにより、構造物の地中構造部分の周囲の軟弱地盤を改良し、地震時の外力によって構造物が倒壊等するのを防止している。
特開平２−３１１６１３号公報 An example of this type of seismic reinforcement method is described in Patent Document 1. This seismic reinforcement method is made by inserting a stirrer into the sand layer (soft layer) of the soft ground where the structure is constructed, and stirring and mixing the solidified material and sand of the sand layer while pumping the cement-based solidified material, By constructing a solidified body that is a solid ground improvement body in a state of surrounding the structure, the lower end of this solidified body is rooted in a solid viscous layer (support layer) below the sand layer. The soft ground around the underground structure is improved to prevent the structure from collapsing due to external force during an earthquake.
Japanese Patent Laid-Open No. 2-311613

ところで、上記のような構成の耐震補強方法にあっては、固結体の下端を砂層の下方の粘性層に根入れさせることにより、地震時の外力によって固結体が滑動、転倒等するのを防止しているため、固結体の容積が大きくなる。このため、地盤改良可能な範囲が制限される市街地等に適用することは難しい。また、固結体の内的安定性を確保するために、固結体の容積を大きくとらなければならないため、固結体の構築に時間と手間と費用がかかる。   By the way, in the seismic reinforcement method having the above-described configuration, the consolidated body slides or falls due to an external force at the time of an earthquake by allowing the lower end of the consolidated body to be embedded in the viscous layer below the sand layer. Therefore, the volume of the consolidated body is increased. For this reason, it is difficult to apply to an urban area where the range where the ground can be improved is limited. In addition, in order to ensure the internal stability of the consolidated body, it is necessary to increase the volume of the consolidated body, so that it takes time, labor and cost to construct the consolidated body.

本発明は、上記のような従来の問題に鑑みなされたものであって、固化系の地盤改良体の容積を小さくすることができ、これにより、地盤改良の範囲が制限される市街地等にも適用できるとともに、固化系の地盤改良体の構築に要する時間と手間と費用とを削減することができる地盤改良体及び地盤改良体の構築方法を提供することを目的とする。   The present invention has been made in view of the above-described conventional problems, and can reduce the volume of the solidified ground improvement body, and thereby, in urban areas where the range of ground improvement is limited. An object of the present invention is to provide a ground improvement body and a method for constructing a ground improvement body that can be applied and can reduce the time, labor, and cost required to construct a solid ground improvement body.

上記のような課題を解決するために、本発明は、以下のような手段を採用している。
すなわち、本発明の地盤改良体は、構造物が構築された軟弱層に前記構造物を囲んだ状態で構築される固化改良体と、該固化改良体の前記構造物側の面又は前記構造物と反対側の面の少なくとも一方に該面と接触するように又は間隔をおいて設けられて、下端が前記軟弱層の下方の支持層に達するように打設された鋼部材とを備えていることを特徴とする。 In order to solve the above problems, the present invention employs the following means.
That is, the ground improvement body of the present invention includes a solidification improvement body constructed in a state in which the structure is surrounded by a soft layer in which the structure is constructed, and the structure-side surface of the solidification improvement body or the structure. And a steel member that is disposed so as to come into contact with or spaced from at least one of the surfaces opposite to the surface and that has a lower end that reaches the support layer below the soft layer. It is characterized by that.

本発明の地盤改良体によれば、固化改良体の構造物側の面又は構造物と反対側の面の少なくとも一方に該面と接触するように又は間隔をおいて鋼部材が設けられ、この鋼部材は、下端が軟弱層の下方の支持層に達するように打設されているので、地盤改良体の滑動や回転抵抗に対して鋼部材により抵抗することができる。
また、地震時の外力による地盤改良体に発生する内部応力に対して鋼部材により抵抗力を分担することができるので、地震時の地盤改良体の内的安定性を確保することができる。
従って、固化改良体のみによって地盤改良体を構成したものに比べて、固化改良体の容積を小さくすることができるので、地盤改良可能な範囲が制限される市街地等に適用することができる。また、地盤改良体の構築に要する時間と手間と費用を削減することができる。 According to the ground improvement body of the present invention, the steel member is provided on at least one of the surface on the structure side of the solidification improvement body or the surface on the opposite side of the structure so as to contact the surface or at intervals. Since the steel member is driven so that the lower end reaches the support layer below the soft layer, the steel member can resist the sliding and rotation resistance of the ground improvement body.
Moreover, since the resistance force can be shared by the steel member against the internal stress generated in the ground improvement body due to the external force at the time of the earthquake, the internal stability of the ground improvement body at the time of the earthquake can be ensured.
Therefore, since the volume of the solidified improvement body can be reduced as compared with a structure in which the ground improvement body is constituted only by the solidification improvement body, it can be applied to an urban area where the range where the ground improvement is possible is limited. Moreover, the time, labor, and cost required for constructing the ground improvement body can be reduced.

また、本発明は、構造物が構築された軟弱層に前記構造物を囲んだ状態で構築される固化改良体と、該固化改良体の内部に、下端が該固化改良体を貫通して前記軟弱層の下方の支持層に達するように打設された鋼部材とを備えていることを特徴とする。   The present invention also relates to a solidification improved body constructed in a state where the structure is surrounded by a soft layer in which the structure is constructed, and the lower end penetrates the solidification improvement body inside the solidification improvement body. And a steel member cast so as to reach the support layer below the soft layer.

本発明の地盤改良体によれば、固化改良体の内部に鋼部材が打設され、この鋼部材の下端は、固化改良体を貫通して軟弱層の下方の支持層に達しているので、地盤改良体の滑動や回転抵抗に対して鋼部材により抵抗することができる。
従って、固化改良体のみによって地盤改良体を構成したものに比べて、固化改良体の容積を小さくすることができるので、地盤改良可能な範囲が制限される市街地等に適用することができる。また、地盤改良体の構築に要する時間と手間と費用を削減することができる。 According to the ground improvement body of the present invention, a steel member is placed inside the solidification improvement body, and the lower end of the steel member penetrates the solidification improvement body and reaches the support layer below the soft layer. The steel member can resist the sliding and rotation resistance of the ground improvement body.
Therefore, since the volume of the solidified improvement body can be reduced as compared with a structure in which the ground improvement body is constituted only by the solidification improvement body, it can be applied to an urban area where the range where the ground improvement is possible is limited. Moreover, the time, labor, and cost required for constructing the ground improvement body can be reduced.

さらに、本発明は、前記固化改良体は、前記構造物と間隔をおいて構築されていることを特徴とすることとしてもよい。   Furthermore, the present invention may be characterized in that the solidification improving body is constructed at a distance from the structure.

本発明の地盤改良体によれば、固化改良体は、構造物と間隔をおいて構築されているので、固化改良体と構造物との間に軟弱層を構成する砂、土等が介在することになる。従って、この砂、土等を緩衝材として機能させることができるので、地震時に構造物と地盤改良体との間に相対的な変動が生じた場合に、その変動を構造物と地盤改良体との間の軟弱層の砂、土等によって緩衝することができる。   According to the ground improvement body of the present invention, since the solidification improvement body is constructed at a distance from the structure, sand, soil, etc. constituting a soft layer are interposed between the solidification improvement body and the structure. It will be. Therefore, since this sand, soil, etc. can function as a cushioning material, when a relative change occurs between the structure and the ground improvement body during an earthquake, the change is transferred to the structure and the ground improvement body. Can be buffered by soft layer sand, soil etc. between.

さらに、本発明の地盤改良体の構築方法は、構造物が構築された軟弱層に前記構造物を囲んだ状態で固化改良体を構築し、該固化改良体の前記構造物側の面又は前記構造物と反対側の面の少なくとも一方に該面と接触するように又は間隔をおいて鋼部材を打設して、該鋼部材の下端を前記軟弱層の下方の支持層に到達させることを特徴とする。   Further, in the ground improvement body construction method of the present invention, the solidification improvement body is constructed in a state where the structure is surrounded by the soft layer in which the structure is constructed, and the surface of the solidification improvement body on the structure side or the Placing a steel member on at least one of the surfaces opposite to the structure so as to be in contact with or spaced from the surface, so that the lower end of the steel member reaches the support layer below the soft layer. Features.

さらに、本発明の地盤改良体の構築方法は、構造物が構築された軟弱層に前記構造物を囲んだ状態で固化改良体を構築し、該固化改良体の内部に鋼部材を打設して、該鋼部材の下端を該固化改良体を貫通させて前記軟弱層の下方の支持層に到達させることを特徴とする。   Further, according to the ground improvement body construction method of the present invention, a solidification improvement body is constructed in a state where the structure is surrounded by a soft layer in which the structure is constructed, and a steel member is placed inside the solidification improvement body. Thus, the lower end of the steel member is made to penetrate the solidification improving body to reach the support layer below the soft layer.

以上、説明したように、本発明の地盤改良体及び地盤改良体の構築方法によれば、地盤改良体の滑動や回転抵抗に対して鋼部材により抵抗することができる。また、地震時の外力による地盤改良体に発生する内部応力に対して各鋼部材により抵抗力を分担することができるので、地震時の地盤改良体の内的安定性を確保することができる。
従って、固化改良体のみによって地盤改良体を構成したものに比べて、固化改良体の容積を小さくすることができるので、地盤改良の範囲が制限される市街地等にも適用することができる。また、固化改良体の容積を小さくすることができるので、地盤改良体の構築に要する時間と手間と費用を削減することができる。 As described above, according to the ground improvement body and the construction method of the ground improvement body of the present invention, the steel member can resist the sliding and rotation resistance of the ground improvement body. Moreover, since each steel member can share resistance with respect to the internal stress which generate | occur | produces in the ground improvement body by the external force at the time of an earthquake, the internal stability of the ground improvement body at the time of an earthquake can be ensured.
Therefore, since the volume of the solidified improvement body can be reduced as compared with the case where the ground improvement body is constituted only by the solidification improvement body, the present invention can be applied to urban areas where the range of ground improvement is limited. In addition, since the volume of the solidified improvement body can be reduced, the time, labor, and cost required to construct the ground improvement body can be reduced.

以下、図面を参照しながら本発明の実施の形態について説明する。
図１及び図２には、本発明による地盤改良体の第１の実施の形態が示されている。図１は地盤改良体の断面図、図２は地盤改良体の平面図である。 Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1 and 2 show a first embodiment of a ground improvement body according to the present invention. FIG. 1 is a sectional view of the ground improvement body, and FIG. 2 is a plan view of the ground improvement body.

すなわち、本実施の形態の地盤改良体１は、堅固な支持層２２の上部に軟弱な軟弱層２１（例えば、液状化層）が積層された軟弱地盤２０に地盤改良を施し、軟弱地盤２０に構築されている既設の構造物１０を耐震補強するのに有効なものであって、軟弱地盤２０に構築されている既設の構造物１０の地中構造部分１１を囲むように設けられる固化改良体２と、固化改良体２の構造物側の面３及び構造物と反対側の面４に、その面３、４と接触するようにそれぞれ設けられる鋼部材５とを備えている。   That is, the ground improvement body 1 according to the present embodiment applies the ground improvement to the soft ground 20 in which the soft soft layer 21 (for example, the liquefied layer) is laminated on the solid support layer 22. A solidified improvement body that is effective for seismic reinforcement of an existing structure 10 that is constructed, and is provided so as to surround an underground structure portion 11 of the existing structure 10 that is constructed on a soft ground 20. 2 and steel members 5 provided on the surface 3 on the structure side and the surface 4 on the opposite side of the structure, respectively, so as to be in contact with the surfaces 3 and 4.

固化改良体２は、ＪＳＧ工法（Ｊｕｍｂｏ−Ｊｅｔ−Ｓｐｅｃｉａｌ Ｇｒｏｕｔ Ｍｅｔｈｏｄ）、ＣＪＧ工法（Ｃｏｌｕｍｎ Ｊｅｔ−Ｇｒｏｕｔ Ｍｅｔｈｏｄ）等の各種の工法によって構築される。   The solidification improvement body 2 is constructed | assembled by various construction methods, such as a JSG construction method (Jumbo-Jet-Special Grouting Method) and a CJG construction method (Column Jet-Grout Method).

例えば、ＪＳＧ工法による場合には、ＪＳＧ装置を軟弱地盤２０の対象箇所に設置し、ＪＳＧ装置の二重管ロッドを回転させて、二重管ロッドの先端からセメントミルク等の硬化材と圧縮空気とを高圧で噴射しながら、二重管ロッドを軟弱地盤２０の軟弱層２１に所定の深度まで挿入することにより、軟弱層２１の砂、土等と硬化材とが混合されて固化され、所定の厚さ、深度の固化改良体２が構築される。   For example, in the case of the JSG method, the JSG device is installed at a target location on the soft ground 20, the double tube rod of the JSG device is rotated, and a hardening material such as cement milk and compressed air are rotated from the tip of the double tube rod. Is inserted into the soft layer 21 of the soft ground 20 to a predetermined depth while the sand, soil, etc. of the soft layer 21 and the hardener are mixed and solidified, The solidification improvement body 2 of thickness and depth is constructed.

固化改良体２は、軟弱地盤２０に構築されている構造物１０の地中構造部分１１の形状に応じた形状に構築される。本実施の形態においては、構造物１０の地中構造部分１１は、平面視四角形状の基礎１２と、基礎１２を支持する下端が支持層２２に根入れされた複数の杭１３とから構成されているので、この地中構造部分１１の周囲を囲むように、地中構造部分１１の外側に所定の間隔をおいて固化改良体２が角環状に構築されている。   The solidified improvement body 2 is constructed in a shape corresponding to the shape of the underground structure portion 11 of the structure 10 constructed on the soft ground 20. In the present embodiment, the underground structure portion 11 of the structure 10 includes a foundation 12 having a rectangular shape in plan view, and a plurality of piles 13 in which a lower end supporting the foundation 12 is embedded in a support layer 22. Therefore, the solidification improving body 2 is constructed in an annular shape at a predetermined interval outside the underground structure portion 11 so as to surround the periphery of the underground structure portion 11.

固化改良体２は、下端が支持層２２まで達しないように、構造物１０の地中構造部分１１の外側に所定の間隔をおいて、かつ地中構造部分１１の全周を囲むように、所定の厚さ、深度で構築され、この固化改良体２の構造物側の面３及び構造物と反対側の面４にそれぞれ鋼部材５が打設されている。   The solidification improvement body 2 is spaced a predetermined distance outside the underground structure portion 11 of the structure 10 so that the lower end does not reach the support layer 22, and surrounds the entire circumference of the underground structure portion 11. A steel member 5 is cast on each of the surface 3 on the structure side and the surface 4 on the opposite side of the structure.

鋼部材５は、Ｕ形、直線形等の鋼矢板、Ｈ形鋼、Ｉ形鋼等の形鋼、鋼管等の構造用鋼材から構成されるものであって、固化改良体２の構造物側の面３及び構造物と反対側の面４に接触するように、固化改良体２の構造物側の面３及び構造物と反対側の面４にそれぞれ打設されている。   The steel member 5 is composed of a steel sheet pile such as a U-shape or a straight shape, a shape steel such as an H-shape steel or an I-shape steel, or a structural steel material such as a steel pipe. The surface 3 and the surface 4 opposite to the structure of the solidification improving body 2 are placed so as to contact the surface 3 and the surface 4 opposite to the structure.

この場合、固化改良体２の構造物側の面３及び構造物と反対側の面４の全体を覆うように、複数の鋼部材５が固化改良体２の構造物側の面３及び構造物と反対側の面４に全周に亘って連続して打設されている。また、各鋼部材５は、下端が軟弱層２１を貫通して軟弱層２１の下方の支持層２２に根入れされるように、固化改良体２の構造物側の面３及び構造物と反対側の面４に打設されている。   In this case, the plurality of steel members 5 are arranged on the structure-side surface 3 and the structure of the solidification improved body 2 so as to cover the entire surface 3 and the surface 4 opposite to the structure of the solidification-improved body 2. Is continuously driven over the entire circumference on the surface 4 on the opposite side. Also, each steel member 5 is opposite to the structure-side surface 3 and the structure of the solidified improvement body 2 so that the lower end penetrates the soft layer 21 and is embedded in the support layer 22 below the soft layer 21. It is placed on the side surface 4.

これにより、地震時の外力による地盤改良体１に発生する内部応力に対して各鋼部材５により抵抗力を分担することができるので、地震時の地盤改良体１の内的安定性を確保することができる。また、各鋼部材５が地盤改良体１を貫通して支持層２２に根入れ（貫入）されていることにより、地震時に地盤改良体１が滑動したり転倒したりするのを防止できる。
従って、地震時に地盤改良体１の崩壊（内的安定性の喪失）や、滑動・転倒により構造物１０が倒壊等するのを防止できる。 Thereby, since each steel member 5 can share resistance with respect to the internal stress which generate | occur | produces in the ground improvement body 1 by the external force at the time of an earthquake, the internal stability of the ground improvement body 1 at the time of an earthquake is ensured. be able to. Further, since each steel member 5 penetrates the ground improvement body 1 and is embedded (penetrated) into the support layer 22, it is possible to prevent the ground improvement body 1 from sliding or overturning during an earthquake.
Accordingly, it is possible to prevent the structure 10 from collapsing due to the collapse of the ground improvement body 1 (loss of internal stability) or sliding / falling during the earthquake.

固化改良体２及び鋼部材５は、先にＪＳＧ工法等により固化改良体２を構築し、その後に、固化改良体２の構造物側の面３及び構造物と反対側の面４に各種の圧入機により鋼部材５を打設してもよいし、あるいは、先に構造物１０の地中構造部分１１の外側に各種の圧入機により鋼部材５を二重に打設し、その後に、内側の鋼部材５と外側の鋼部材５との間にＪＳＧ工法等により固化改良体２を構築するように構成してもよい。   The solidification improved body 2 and the steel member 5 are constructed on the surface 3 on the structure side of the solidification improvement body 2 and the surface 4 on the opposite side of the structure after the construction of the solidification improvement body 2 by the JSG method or the like. The steel member 5 may be driven by a press-fitting machine, or the steel member 5 may be double-pumped by various press-fitting machines on the outside of the underground structure portion 11 of the structure 10 first, You may comprise so that the solidification improvement body 2 may be constructed | assembled by the JSG method etc. between the inner side steel member 5 and the outer side steel member 5. FIG.

上記のように構成した本実施の形態による地盤改良体１にあっては、固化改良体２の構造物側の面３及び構造物と反対側の面４に鋼部材５を打設して、鋼部材５の下端を軟弱層２１の下方の支持層２２に根入れさせているので、固化改良体２の滑動や回転抵抗に対して鋼部材５により抵抗することができる。   In the ground improvement body 1 according to the present embodiment configured as described above, the steel member 5 is driven on the surface 3 on the structure side and the surface 4 on the opposite side of the structure of the solidification improvement body 2, Since the lower end of the steel member 5 is embedded in the support layer 22 below the soft layer 21, the steel member 5 can resist the sliding and rotation resistance of the solidification improving body 2.

従って、固化改良体２の深度、及び容積を小さくしても、固化改良体のみによって地盤改良体を構成した従来のものと同程度の強度が得られるので、地盤改良の範囲が制限される市街地等にも適用することができる。
また、固化改良体２の深度、容積を小さくすることができるので、地盤改良体１の構築に要する時間と手間と費用を削減することができる。 Therefore, even if the depth and volume of the solidified improvement body 2 are reduced, the strength equivalent to that of the conventional structure in which the ground improvement body is constituted only by the solidification improvement body can be obtained. The present invention can also be applied.
In addition, since the depth and volume of the solidified improvement body 2 can be reduced, the time, labor, and cost required for the construction of the ground improvement body 1 can be reduced.

さらに、地盤改良体１を構造物１０の地中構造部分１１の外側に間隔をおいて設けているので、この間隔内に介在している軟弱層２１の砂、土等を緩衝材として機能させることができる。従って、地震時に構造物１０の地中構造部分１１と地盤改良体１との間に相対的な変動が生じた場合に、その変動を間隔内に介在している軟弱層１２の砂や土等によって緩衝させることができる。   Further, since the ground improvement body 1 is provided at intervals outside the underground structure portion 11 of the structure 10, the sand, soil, etc. of the soft layer 21 interposed in this interval function as a cushioning material. be able to. Therefore, when a relative change occurs between the underground structure portion 11 of the structure 10 and the ground improvement body 1 at the time of the earthquake, the sand, soil, etc. of the soft layer 12 intervening the change within the interval. Can be buffered.

さらに、鋼部材５に鋼矢板を用い、鋼矢板によって構造物１０の地中構造部分１１の全周を囲んだ場合には、地盤改良体１の内的安定性を鋼矢板からなる鋼部材５によって有効に確保することができる。   Furthermore, when a steel sheet pile is used for the steel member 5 and the entire circumference of the underground structural portion 11 of the structure 10 is surrounded by the steel sheet pile, the steel member 5 made of a steel sheet pile is used for the internal stability of the ground improvement body 1. Can be effectively secured.

なお、前記の説明においては、固化改良体２の構造物側の面３及び構造物と反対側の面４に接触した状態で鋼部材５を打設したが、固化改良体２の構造物側の面３及び構造物と反対側の面４に間隔をおいて鋼部材５を打設してもよい。   In the above description, the steel member 5 is placed in contact with the surface 3 on the structure side of the solidified improvement body 2 and the surface 4 on the opposite side of the structure. The steel member 5 may be driven with a space between the surface 3 and the surface 4 opposite to the structure.

また、前記の説明においては、固化改良体２の構造物側の面３及び構造物と反対側の面４の両方に鋼部材５を打設したが、固化改良体２の構造物側の面３又は構造物と反対側の面４の何れか一方に鋼部材５を打設してもよい。   In the above description, the steel member 5 is placed on both the surface 3 on the structure side of the solidified improvement body 2 and the surface 4 on the side opposite to the structure, but the surface on the structure side of the solidification improved body 2. 3 or the steel member 5 may be placed on either the surface 4 opposite to the structure.

図３及び図４には、本発明による地盤改良体１の第２の実施の形態が示されている。この地盤改良体１は、固化改良体２の内部に鋼部材５を打設し、この鋼部材５の下端を固化改良体２を貫通させて軟弱層２１の下方の支持層２２に根入れさせたものであって、その他の構成は前記第１の実施の形態に示すものと同様である。   3 and 4 show a second embodiment of the ground improvement body 1 according to the present invention. The ground improvement body 1 has a steel member 5 placed inside the solidification improvement body 2 and the lower end of the steel member 5 penetrates the solidification improvement body 2 and is rooted in the support layer 22 below the soft layer 21. The other configurations are the same as those shown in the first embodiment.

そして、本実施の形態による地盤改良体１にあっても、固化改良体２の内部に鋼部材５を打設して、鋼部材５の下端を軟弱層２１の下方の支持層２２に根入れさせているので、固化改良体２の滑動や回転抵抗に対して鋼部材５により抵抗することができる。   And even if it exists in the ground improvement body 1 by this Embodiment, the steel member 5 is driven inside the solidification improvement body 2, and the lower end of the steel member 5 is rooted in the support layer 22 below the soft layer 21. Therefore, the steel member 5 can resist the sliding and rotation resistance of the solidification improving body 2.

従って、固化改良体２の深度、及び容積を小さくしても、固化改良体のみによって地盤改良体を構成した従来のものと同程度の強度が得られるので、地盤改良の範囲が制限される市街地等にも適用することができる。
また、固化改良体２の深度、容積を小さくすることができるので、地盤改良体１の構築に要する時間と手間と費用を削減することができる。 Therefore, even if the depth and volume of the solidified improvement body 2 are reduced, the strength equivalent to that of the conventional structure in which the ground improvement body is constituted only by the solidification improvement body can be obtained. The present invention can also be applied.
In addition, since the depth and volume of the solidified improvement body 2 can be reduced, the time, labor, and cost required for the construction of the ground improvement body 1 can be reduced.

さらに、地盤改良体１を構造物１０の地中構造部分１１の外側に間隔をおいて設けているので、この間隔内に介在している軟弱層２１の砂、土等を緩衝材として機能させることができる。従って、地震時に構造物１０の地中構造部分１１と地盤改良体１との間に相対的な変動が生じた場合に、その変動を間隔内に介在している軟弱層１２の砂や土等によって緩衝させることができる。   Further, since the ground improvement body 1 is provided at intervals outside the underground structure portion 11 of the structure 10, the sand, soil, etc. of the soft layer 21 interposed in this interval function as a cushioning material. be able to. Therefore, when a relative change occurs between the underground structure portion 11 of the structure 10 and the ground improvement body 1 at the time of the earthquake, the sand, soil, etc. of the soft layer 12 intervening the change within the interval. Can be buffered.

本発明による地盤改良体の第１の実施の形態を示した断面図である。It is sectional drawing which showed 1st Embodiment of the ground improvement body by this invention. 図１の平面図である。It is a top view of FIG. 本発明による地盤改良体の第２の実施の形態を示した断面図である。It is sectional drawing which showed 2nd Embodiment of the ground improvement body by this invention. 図３の平面図である。FIG. 4 is a plan view of FIG. 3. 従来の地盤改良体の一例を示した断面図である。It is sectional drawing which showed an example of the conventional ground improvement body.

符号の説明Explanation of symbols

１、１５ 地盤改良体
２ 固化改良体
３ 構造物側の面
４ 構造物と反対側の面
５ 鋼部材
１０ 構造物
１１ 地中構造部分
１２ 基礎
１３ 杭
２０ 軟弱地盤
２１ 軟弱層
２２ 支持層 DESCRIPTION OF SYMBOLS 1,15 Ground improvement body 2 Solidification improvement body 3 Surface on the structure side 4 Surface on the opposite side to a structure 5 Steel member 10 Structure 11 Underground structure part 12 Foundation 13 Pile 20 Soft ground 21 Soft layer 22 Support layer

Claims (5)

構造物が構築された軟弱層に前記構造物を囲んだ状態で構築される固化改良体と、該固化改良体の前記構造物側の面又は前記構造物と反対側の面の少なくとも一方に該面と接触するように又は間隔をおいて設けられて、下端が前記軟弱層の下方の支持層に達するように打設された鋼部材とを備えていることを特徴とする地盤改良体。   A solidified improvement body constructed in a state where the structure is surrounded by a soft layer in which the structure is constructed, and at least one of the surface of the solidification improvement body on the structure side or the surface opposite to the structure A ground improvement body comprising: a steel member that is provided so as to come into contact with a surface or at an interval, and that has a lower end that reaches a support layer below the soft layer. 構造物が構築された軟弱層に前記構造物を囲んだ状態で構築される固化改良体と、該固化改良体の内部に、下端が該固化改良体を貫通して前記軟弱層の下方の支持層に達するように打設された鋼部材とを備えていることを特徴とする地盤改良体。   A solidified improvement body constructed in a state where the structure is surrounded by a soft layer in which the structure is constructed, and a lower end penetrating the solidification improvement body inside the solidification improvement body and supporting below the soft layer A ground improvement body comprising a steel member placed so as to reach a layer. 前記固化改良体は、前記構造物と間隔をおいて構築されていることを特徴とする請求項１又は２に記載の地盤改良体。   The ground improvement body according to claim 1 or 2, wherein the solidification improvement body is constructed at an interval from the structure. 構造物が構築された軟弱層に前記構造物を囲んだ状態で固化改良体を構築し、該固化改良体の前記構造物側の面又は前記構造物と反対側の面の少なくとも一方に該面と接触するように又は間隔をおいて鋼部材を打設して、該鋼部材の下端を前記軟弱層の下方の支持層に到達させることを特徴とする地盤改良体の構築方法。   A solidified improvement body is constructed in a state where the structure is surrounded by a soft layer in which the structure is constructed, and the surface is provided on at least one of the surface of the solidification improvement body and the surface opposite to the structure. A method for constructing a ground improvement body, wherein a steel member is placed so as to come into contact with or spaced from each other, and the lower end of the steel member reaches a support layer below the soft layer. 構造物が構築された軟弱層に前記構造物を囲んだ状態で固化改良体を構築し、該固化改良体の内部に鋼部材を打設して、該鋼部材の下端を該固化改良体を貫通させて前記軟弱層の下方の支持層に到達させることを特徴とする地盤改良体の構築方法。   A solidified improvement body is constructed in a state where the structure is surrounded by a soft layer in which the structure is constructed, a steel member is placed inside the solidification improvement body, and the lower end of the steel member is attached to the solidification improvement body. A method for constructing a ground improvement body, characterized in that the ground improvement body is made to penetrate and reach a support layer below the soft layer.
JP2008285793A 2008-11-06 2008-11-06 Ground improvement body and construction method of ground improvement body Expired - Fee Related JP5206333B2 (en)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH02311613A (en) * 1989-05-24 1990-12-27 Sumitomo Cement Co Ltd Liquefaction preventing construction method for sand ground
JPH1018308A (en) * 1996-07-02 1998-01-20 Taisei Corp Liquefaction prevention structure for building ground
JP2000273881A (en) * 1999-03-24 2000-10-03 Toyo Constr Co Ltd Aseismatic reinforcing construction method for existing structure foundation
JP2001214465A (en) * 2000-01-31 2001-08-07 Sumitomo Metal Ind Ltd Reinforcing structure for underground construction

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH02311613A (en) * 1989-05-24 1990-12-27 Sumitomo Cement Co Ltd Liquefaction preventing construction method for sand ground
JPH1018308A (en) * 1996-07-02 1998-01-20 Taisei Corp Liquefaction prevention structure for building ground
JP2000273881A (en) * 1999-03-24 2000-10-03 Toyo Constr Co Ltd Aseismatic reinforcing construction method for existing structure foundation
JP2001214465A (en) * 2000-01-31 2001-08-07 Sumitomo Metal Ind Ltd Reinforcing structure for underground construction

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