JP4027264B2 - How to construct soil cement composite piles - Google Patents

How to construct soil cement composite piles Download PDF

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JP4027264B2
JP4027264B2 JP2003131370A JP2003131370A JP4027264B2 JP 4027264 B2 JP4027264 B2 JP 4027264B2 JP 2003131370 A JP2003131370 A JP 2003131370A JP 2003131370 A JP2003131370 A JP 2003131370A JP 4027264 B2 JP4027264 B2 JP 4027264B2
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soil cement
wing
steel pipe
liquid
pile
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JP2004332431A (en
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信一 日比野
篤史 村山
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株式会社テノックス
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Description

【0001】
【産業上の利用分野】
この発明はソイルセメント柱中に少なくとも下方の外側面に翼部を有する鋼管杭が埋設されたソイルセメント合成杭を施工する方法に関し、特には下部に固化材の豊富なソイルセメント部分が築造されたソイルセメント合成杭を施工する方法に関する。
【0002】
なお、ソイルセメントとは、セメントミルク等の固化材液と掘削土、例えば掘削翼によって掘削された土砂とセメントミルク等の固化材液とが攪拌混合されて築造されるものであり、これが柱状に築造されたものをソイルセメント柱という。また、ソイルセメント柱の中に鋼管杭が埋設されたものをソイルセメント合成杭という。
【0003】
【従来の技術】
ソイルセメント柱中に少なくとも下方の外側面に翼部を有する鋼管杭が埋設されたソイルセメント合成杭を施工する従来の方法は、単にソイルセメント柱中に翼部を有する鋼管杭を埋設するものであった(例えば、特許文献1と2参照)。
【0004】
また、翼部を有する鋼管杭の下方部分にソイルセメントの根固め部を築造することも知られていた(例えば、特許文献3と4参照)。
【0005】
更に地中に吐出した固化材液を練り返すことによってソイルセメントの品質がばらつかず、その結果強度が高くなることも公知であった(例えば、特許文献5参照)。
【0006】
【特許文献1】
特開2001−317050号公報(図1,2)
【特許文献2】
特開2002−201638号公報(図2)
【特許文献3】
特開2000−291002号公報(図1、図2及び[0012])
【特許文献4】
特許第2731806号公報(第1f図と請求項1)
【特許文献5】
特開2001−040653号(図3〜図5と請求項1)
【0007】
【発明が解決しようとする課題】
上記したように、ソイルセメント柱中に少なくとも下部に固化材液の吐出口を有しかつ掘削翼と攪拌翼を少なくとも有する装置にて固化材液を地中に吐出すると共にその装置を回転させることにより固化材液と掘削土とを攪拌混合しながら掘進し、豊富なソイルセメント部としたソイルセメント柱を築造した後に、そのソイルセメント柱中に前記の少なくとも下方の外周面に翼部を有する鋼管杭を埋設することは知られていた。
【0008】
しかしながら従来方法では、下端部の固化材の豊富なソイルセメント部すなわち根固め部を築造するために、地上から掘進していく際に吐出される固化材液の濃度よりも高い濃度の固化材液に切り替えて、根固め部を築造していた。それ故、固化材液を切り替えるのは時間がかかり、かつ2種類の濃度の固化材液を準備する必要があり、施工コストが高くなっている。
【0009】
この発明の第1の目的は、施工コストの上昇を抑えるため、1種類の濃度の固化材液を準備するだけで施工しても、ソイルセメント柱中に少なくとも下方の外側面に翼部を有する鋼管杭が埋設されたソイルセメント合成杭が所定の支持力を発揮することが可能な施工方法を提供することである。
【0010】
また、従来方法に基づいてソイルセメント柱中に少なくとも下方の外側面に翼部を有する鋼管杭が埋設されたソイルセメント合成杭を施工する方法において、下方の外側面に翼部を有する鋼管杭として翼部の外径Dが翼部を除く部分の外径dの約1.5倍以上2.5倍未満でかつ20〜70cmであり、翼部を除く部分の外径dが10〜40cmである鋼管杭を使用して、下部に固化材液の吐出口を有しかつ掘削翼と攪拌翼を少なくとも有する装置にて固化材液を地中に吐出すると共にその装置を回転させることにより固化材液と掘削土とを攪拌混合しながら所定の地盤まで掘進し、地中に前記翼部の外径Dの1.2倍〜2倍程度でかつ40cm以上120cm以下の外径のソイルセメント柱を築造しながら、ソイルセメント柱の最下部から前記翼部の外径Dの1〜2倍程度の範囲に固化材の豊富なソイルセメント部分を築造し、その後に前記した鋼管杭を回転させながら埋設することによりソイルセメント合成杭としても、その下端のN値が20未満である場合は、ソイルセメント合成杭はその地盤に見合う支持力が得られていた。しかしながら、理由は不明であるが、先端N値が22以上になると、その地盤、即ち、支持地盤に見合う高い支持力が発現できるソイルセメント合成杭とならなかった。
【0011】
このときに、上記した特許文献5に示された地中に吐出した固化材液を吐出することなく、練り返す作業を加えても、先端N値が22以上となると、その地盤のN値に見合う支持力を有するソイルセメント合成杭は得られなかった。
【0012】
この発明の第2の目的は、先端N値が22以上となる地盤まで掘進して根固め部分を有するソイルセメント柱を築造し、その中に前記した大きさの翼部を少なくとも下部の外側面に有する鋼管杭を埋設することによりソイルセメント合成杭とした場合でも、先端N値が22以上となる地盤即ち支持地盤に見合う高い支持力が発現できるソイルセメント合成杭とするためのソイルセメント合成杭を施工する方法を提供することにある。
【0013】
【課題を解決するための手段】
第1の発明は、請求項1に記載した発明であり、ソイルセメント柱中に少なくとも下方の外側面に翼部を有する鋼管杭が埋設されたソイルセメント合成杭を施工する方法において、下部に固化材液吐出口を有しかつ掘削翼と攪拌翼を少なくとも有する装置にて、固化材液を地中に吐出すると共にその装置を回転させることにより固化材液と掘削土とを攪拌混合しながら所定の地盤まで掘進し、地中にソイルセメント柱を築造した後に、ソイルセメント柱の最下部から前記翼部の外径Dの1〜2倍程度の範囲まで装置を引き上げ、その後、固化材液濃度を変えることなく固化材液を吐出しかつ装置を回転しながら、かつ下降させることによりソイルセメント柱の最下部から前記翼部の引き上げ位置までの範囲に固化材の豊富なソイルセメント部分を築造し、その後に鋼管杭の下方外側面の翼部が固化材の豊富なソイルセメント部分に位置するように鋼管杭を埋設することを特徴とするソイルセメント合成杭を施工する方法である。
【0014】
このように、この発明では固化材の豊富なソイルセメント部分の築造の際に固化液濃度を変える必要がないので、1種類の濃度の固化材液を準備するだけで、固化材の豊富なソイルセメント部を築造でき、下方の外側面に翼部を有する鋼管杭がソイルセメント柱中に埋設されたソイルセメント合成杭が所定の支持力を発揮し得るのである。
【0015】
この固化材の豊富なソイルセメント部分を築造する際、掘進時の速度と同じ速度で下降させることにより固化材の豊富なソイルセメント部分を築造すると、ソイルセメント柱全体の築造時間を最も短くでき、かつ固化材液の吐出を停止して、下部に固化材液の吐出口を有しかつ掘削翼と掘削翼を有する装置を最下端から回転させながら引き上げる際にも攪拌混合されるので良質なソイルセメント柱を築造することができる。
【0016】
なお、この発明の固化材の豊富なソイルセメント部分は、最初の掘進時に吐出された固化材液と次に下降する際に吐出された固化材液との2度の吐出により固化材の豊富な部分となるのである。それ故掘進時の速度と同じ速度で下降させ
る場合は、固化材の豊富なソイルセメント部分は、この発明のために用意した1種類の濃度の固化材液が2度同じ速度で吐出される故に、固化材量が2倍となったソイルセメント部分となるのである。
【0017】
地盤によってソイルセメント杭に要求される支持力が高い場合は、準備する固化材液の濃度を高くすることができる。その場合、ソイルセメント柱の上部部分も固化材の多いソイルセメント部分となるが、その結果、上部のソイルセメントの強度も高くなり、上部にも外側面に翼部を有する鋼管杭を使用した場合、上部の翼部とソイルセメント部の一体性も高まり、地震時等に横向きの力が加わった場合における耐力が一層高いソイルセメント合成杭になる。
【0018】
上記のように、少なくとも下方の外側面に翼部を有する鋼管杭として翼部の外径Dが翼部を除く部分の外径dの約1.5倍以上2.5倍未満でかつ20〜70cmであり、翼部を除く部分の外径dが約10〜40cmである鋼管杭を使用して、下部に固化材液の吐出口を有しかつ掘削翼と攪拌翼を有する装置にて固化材液を地中に吐出すると共にその装置を回転させることにより固化材液と掘削土とを攪拌混合しながら先端N値が22以上となる地盤まで掘進し、地中に前記翼部の外径Dの1.2倍〜2倍程度でかつ40cm以上120cm以下の外径のソイルセメント柱を築造し、前記した鋼管杭を埋設するというソイルセメント合成杭を施工する方法の場合は、ソイルセメント柱下部の強度が低いと、細い鋼管杭に構築物の荷重が集中するので、下部のソイルセメント柱が破壊し、ソイルセメント合成杭として高い支持力が期待できなくなる。そこで、下部に固化材液の吐出口を有しかつ掘削翼と攪拌翼を有する装置にて固化材液を地中に吐出すると共にその装置を回転させることにより固化材液と掘削土を攪拌混合しながら、先端N値が22以上の地盤まで掘進し、地中に前記翼部の外径Dの1.2倍〜2倍程度でかつ40cm以上120cm以下の外径のソイルセメント柱を築造した後に、ソイルセメント柱の最下部から前記翼部の外径Dの1〜2倍程度の範囲まで装置を引き上げ、その後、固化材液濃度を変えることなく固化材液を吐出しかつ装置を回転しながら下降させることによりソイルセメント柱の最下部から前記翼部の引き上げ位置までの範囲に固化材の豊富なソイルセメント部分を築造し、その後に鋼管杭の翼部を除く部分の外径dの最下端部がソイルセメント柱の最下端から20cm程度〜30cm程度上方に位置するように鋼管杭を埋設することによりソイルセメント合成杭を施工するのである。この場合でも鋼管杭の下方外側面の翼部が固化材の豊富なソイルセメント部分に位置することになる。このような施工方法によって、細い鋼管杭を使用しても、ソイルセメント合成杭は、先端N値が22以上となる地盤即ち支持地盤に見合う高い支持力が発現できるのである。
【0019】
この場合、より高い支持力とするためには、最下部から前記翼部の外径Dの1〜2倍程度の範囲までに築造する固化材の豊富なソイルセメント部分における固化材が該部分における単位体積(1m)当たり少なくとも500kg程度添加されていることが望ましい。
【0020】
また、上記したいずれの発明の場合も、使用する鋼管杭が、下方の外側面に翼部を有すると共に上方部の外側面に翼を有する鋼管杭であると、上部でもソイルセメント柱との一体性が高められ、その結果として、鉛直方向のみならず地震時等に横向きの力が加わった場合にも耐力が高いソイルセメント合成杭となる。
【0021】
勿論、使用する鋼管杭が下方の外側面と上方部の外側面の翼部以外に中間部の外側面に翼部を有する杭であっても差し支えない。
【0022】
さらに、この発明に使用する鋼管杭は、数本を継ぎ杭したものでもよいが、その場合には継ぎ杭した状態で、その最下端部の杭の下端部に翼部があり、更には継ぎ杭した最上端部の杭の地上部に近い部分に翼部があるものも、この発明では下方の外側面に翼部を有すると共に、上方部の外側面に翼を有する鋼管杭という。また鋼管杭同士を接続する場合、溶接による接続よりもネジ式継手とすることが施工上の点から好ましい。
【0023】
なお、この発明において、先端N値とは、鋼管杭の先端より下方へ1D、上方へ1Dの間の地盤の平均値(平均N値)を指し、先端N値が22以上となる地盤とはこの平均N値が22以上の地盤を指す。すなわち鋼管杭の本体部3dの下端に突起部3eが存在する場合は、この突起部3eを除いた鋼管杭の最下端部が先端部である。
【0024】
次にこの発明のソイルセメント合成杭を施工する方法の一例について図面を用いて説明する。
【0025】
図1は施工工程図であり、図1にて用いられているソイルセメント柱築造装置1は、図2に示すように、中空状のロッド1aの下方部分に固化材の吐出口1bを有し、かつロッド1aの外周に掘削翼1cと攪拌翼1dを有し、ロッド1aの回転が伝達されないようにロッド1aに枢着された共回り防止翼1eを有する装置である。この共回り防止翼1eは、その外径が掘削翼1cや攪拌翼1dよりも大きく、掘削翼で攪拌された掘削土がロッドの回転と同じように回転すること即ち、共回りを防止する役割をするものである。またこの装置にはロッドの1a最先端部には先端掘削刃1fが設けられている。しかしソイルセメント柱が築造できるのであれば、下部に固化材液の吐出口を有し、かつ掘削翼と攪拌翼を有する装置がこの発明ではソイルセメント柱築造装置として使用できる。
【0026】
また図1に示す下方の外側面に翼部を有する鋼管杭3は、図3に示すように、下方の外側面に翼部、図示した例では螺旋状の翼部3aを有する鋼管製の杭である。図示した例では上方の外周面や中間部の外周面に翼部(図示した例では螺旋状の翼部)3b、3cを有すると共に鋼管杭の本体部即ち、翼を除いた部分3dの下端に板状の突起部3eを有するものである。なお、この突起部3eを除いた鋼管杭の本体部(即ち翼を除いた部分)3dの最下端を鋼管杭の最下端部という。先端に板状の突起部は存在しなくても良く、その場合は、鋼管杭の下端部が最下端部である。
【0027】
なお、この発明で好ましく用いられる鋼管杭3は、翼部の外径Dが翼部を除く部分の外径dの約1.5倍以上2.5倍未満でかつ20〜70cmである鋼管杭である。
【0028】
上記に説明した図2のソイルセメント柱築造装置1を使用し、図3に示した鋼管杭3を使用した場合のソイルセメント合成杭を施工する方法の一例の施工工程が図1に示されているのである。
【0029】
図1(a)に示すように、ソイルセメント合成杭4を築造すべき箇所で、ソイルセメント柱築造装置1のロッド1aを図示しない装置(例えばオーガモータ等)で回転させながら下降させると共に吐出口1bからセメントミルク等の固化材液を吐出することにより、掘削土と固化材液が攪拌翼等で攪拌混合され、ソイルセメントが築造される。
【0030】
なお、地表部付近には固化材液が混合されていない部分所謂、空掘り部を存在させたい場合は、その空掘り部の部分を過ぎてから吐出口1bからセメントミルク等の固化材液を吐出すればよい。
【0031】
このようにして図1(b)に示すように、所望の深さまでソイルセメント柱築造装置1が到達したならば、吐出口1bからのセメントミルク等の固化材液の吐出口1bからのセメントミルク等の固化材液の吐出を停止した後、埋設すべき鋼管杭3の翼部外径Dの1〜2倍程度の範囲までロッドを回転させながらその装置1を引き上げる。その状態が図1(c)に示されている。その後、固化材液濃度を変えることなく固化材液を吐出しながらその装置1を回転しながら下降させる。最も下降した状態を図1(d)に示す。
【0032】
その後、吐出口1bからのセメントミルク等の固化材液の吐出を停止してロッドを回転させながら地表へ回収する。回収後の状態を図1(e)に示す。この図に見られるように、ソイルセメント2の下方には固化材の豊富なソイルセメント部分2aが存在するようになる。
【0033】
上記した各工程での固化材液の吐出状況と固化材液を吐出しない状況を、横軸に経過時間、縦軸に深度を取って、図示すると図4のようである。図4において実線で示した部分が固化材液が吐出されている部分であり、破線で示した部分が固化材液が吐出されていない部分である。
【0034】
使用される固化材液の濃度はいずれの部分でも同じであり、図4に示すように、最初の掘進速度と二度目の下降速度も同一である。
【0035】
図1(f)に示したように、下方の外側面に翼部を有する鋼管杭3を回転させながら埋設し、図1(g)に示すように、鋼管杭の下方の外側面の翼部が固化材の豊富なソイルセメント部分2a中に位置させる。
【0036】
このソイルセメントが固化するとソイルセメント合成杭4が高い支持力を発揮するのである。
【0037】
なお、鋼管杭を埋設する際、鋼管杭3の翼部を除く部分の外径dの最下端部とソイルセメント柱の最下端との間隔、図5でL1と示した間隔が少なくとも20cm〜30cm程度存在すると、ソイルセメント合成杭の支持力が最も優れた性能を発揮する。それ故、翼部を除く部分の外径dの最下端部がソイルセメント柱の最下端から、20cm〜30cm程度上方に位置するようにするのが最も好ましい。なお、図5にL2として示した間隔は、前述した鋼管杭3の翼部外径Dの1〜2倍程度の範囲までソイルセメント柱築造装置1を引き上げた距離に相当する。
【0038】
また、築造するソイルセメント柱の外径(図5にDcと示した径)は、使用する鋼管杭の翼部外径Dの1.2倍〜2倍程度でかつ40cm以上120cm以下とすることが最も好ましい。
【0039】
これは、鋼管杭が、その翼部の外径Dが翼部を除く部分の外径dの約1.5倍以上2.5倍未満でかつ20〜70cmである鋼管杭である場合に、余りにソイルセメント柱の径が大きいと、鋼管杭と一体的に挙動し得ない部分が存在し、ソイルセメント合成杭としての性能が低下する恐れがあり、一方の径の細いソイルセメント柱は、均一な混合状態のものとすることが困難であるからである。
【0040】
また、ソイルセメント柱中に下方の外側面に翼部を有する鋼管杭が埋設されたソイルセメント合成杭は、ソイルセメントと鋼管杭が一体化されて優れた性能を発揮するのであるが、その性能を最高に発揮させるためには、鋼管の径と翼部の径を特定した方がよい。鋼管杭の径と翼径との比が小さすぎても大きすぎても、ソイルセメント合成杭としての性能が十分には発揮されない。
【0041】
【実施例】
図6に示した地盤に深さ5.5mまで図2に示した装置を用いて、図1(a)〜(e)に示した工程で施工した。
【0042】
即ち図1(a)〜(b)に示したように、ロッドを回転し、掘削土の単位体積(1m)当たり250kg程度の固化材が添加されるように固化材液を吐出しながら掘進速度1.0m/分で外径700mのソイルセメント柱を築造し、その後、図1(c)に示すように、図2に示した装置を固化材液を吐出させないで0.7mだけ回転させながら引き上げた。その後、図1(d)に示すように、ロッドを回転しつつ先ほどと同じ濃度の固化材液を再度吐出しながら速度1.0m/分で下降させ、図1(e)に示すように、固化材液を吐出させないで図2に示した装置をロッドを回転させながら他上に引き上げた。
【0043】
このようにして0.7mの範囲に固化材が豊富な部分を築造した。この部分における固化材はその部分における体積当たり(即ち、この部分の掘削体積1m当たり)少なくとも500kg程度添加されている。
【0044】
なお、この地盤の先端N値は50であった。
【0045】
このソイルセメント柱が未硬化の状態で、図3に示した形状の鋼管杭を図1(f)〜(g)に示すように埋設した。即ち、鋼管杭の下方外側面の翼部が固化材の豊富なソイルセメント部分に位置させるようにした。
【0046】
用いた鋼管杭は、翼部の外径Dが500mmで、翼部を除く部分の外径dが267.4mmで、長さが5.5mのものであった。
【0047】
また、この鋼管杭の下端部は、ソイルセメント柱の最下端より200mm上に位置するようにした。
【0048】
このように施工したソイルセメント合成杭を、ソイルセメントの硬化した施工後28日目に支持力を測定した。支持力は4200KNであった。
【0049】
参考のために、ソイルセメント合成杭を掘り出して、ソイルセメントの強度を調査した。結果を図7に示すが、下部のソイルセメントの強度は8.8N/mmであった。
【0050】
なお、深度毎にソイルセメントの一軸圧縮強度を図7に示した。
【0051】
【比較例】
比較例として図1の(c)と(d)の工程を実施することなく、即ち、下部に固化材が豊富な部分を築造することがないという条件を除いて、実施例と同じ条件でソイルセメント合成杭を施工した。このソイルセメント合成杭の支持力は1900KNであった。参考のために、ソイルセメント合成杭を掘り出して、ソイルセメントの強度を調査した。その結果を図7に示すが、下部のソイルセメントの強度は3.0N/mmであった。
【0052】
【発明の効果】
この発明に従えば、地中にソイルセメント柱を築造した後、ソイルセメント柱の最下部から前記翼部の外径Dの1〜2倍程度の範囲まで装置を引き上げ、その後、固化材液濃度を変えることなく固化材液を吐出しながら装置を回転しながら下降させることによりソイルセメント柱の最下部から前記翼部の引き上げ位置までの範囲に固化材の豊富なソイルセメント部分を築造するので、用意する固化材液の濃度は1種類だけであると共に、固化材の豊富なソイルセメント部を有するソイルセメント柱を築造するための施工時間が実質的には短くなる。
【0053】
また、最初に築造したソイルセメント柱の最下部から前記翼部の外径Dの1〜2倍程度範囲は、次の装置の引き上げで再度攪拌混合されて、掘削土と固化材液とが均一に混合された状態になり、次に固化材液を吐出しながら装置を回転しながら下降させることによって均一となったソイルセメントに固化材液が更に吐出されながら攪拌混合され、次の装置の引き上げ時にも再度混合攪拌される。それ故、固化材の豊富なソイルセメント部分は、掘削土と固化材液が十分に混合され均一な状態とすることができる。
【0054】
それ故、鋼管杭の下方の外側面の翼部が固化材の豊富なソイルセメント部分中に位置するように鋼管杭を埋設するので高い支持力を有するソイルセメント杭とすることができる。例えば、先端N値が22以上となる支持地盤内にソイルセメントの先端を到達させた場合でも、その支持地盤に見合う高い支持力を有するソイルセメント杭とすることができる。
【0055】
更に、鋼管杭の翼部を除く部分の外径dの最下端部がソイルセメント柱の最下端から20cm程度〜30cm程度上方に位置するように鋼管杭を埋設すると、ソイルセメント合成杭により支持する上部構造物の荷重が、鋼管杭本体部に伝達されて、最下部の翼部から支持地盤に伝達されるが、この翼部から支持地盤までの距離が20cm程度〜30cm程度あるので、かつ固化材の豊富なソイルセメント部分は十分な強度があるので、ソイルセメント底部の支持地盤に分散して伝達されると共に、固化材の豊富なソイルセメント部分は十分な強度があり強い周面摩擦力による支持力を発揮する。それ故、ソイルセメント合成杭はより高い性能を発揮することができる。
【図面の簡単な説明】
【図1】この発明の施工工程の一例を示す図である。
【図2】この発明で使用するソイルセメント柱築造装置の一例を示す図である。
【図3】この発明で使用する鋼管杭の一例を示す立面図と平面図である。
【図4】この発明のソイルセメント柱築造時の深度と固化材液吐出状態の関係を示す図である。
【図5】この発明によるソイルセメント合成杭の先端部を示す図である。
【図6】実施例で試験した地盤状況を示す図である。
【図7】ソイルセメントの圧縮強度を示すグラフである。
【符号の説明】
1…ソイルセメント柱築造装置、2…ソイルセメント、3…鋼管杭、4…ソイルセメント合成杭。
[0001]
[Industrial application fields]
The present invention relates to a method of constructing a soil cement synthetic pile in which a steel pipe pile having a wing portion is embedded in at least a lower outer surface in a soil cement column, and in particular, a soil cement portion rich in solidifying material is built in a lower portion. The present invention relates to a method for constructing a soil cement synthetic pile.
[0002]
In addition, soil cement is a solidified material liquid such as cement milk and excavated soil, for example, earth and sand excavated by a drilling blade and a solidified material liquid such as cement milk is agitated and built, and this is columnar. The built one is called soil cement pillar. In addition, steel pipe piles embedded in soil cement pillars are called soil cement composite piles.
[0003]
[Prior art]
The conventional method of constructing a soil cement composite pile in which a steel pipe pile having wings at least on the lower outer surface is embedded in a soil cement column is simply to embed a steel pipe pile having wings in the soil cement column. (For example, see Patent Documents 1 and 2).
[0004]
It has also been known to build a solid cement cement portion in the lower part of a steel pipe pile having wings (see, for example, Patent Documents 3 and 4).
[0005]
Furthermore, it has been known that the quality of the soil cement does not vary by kneading the solidifying material liquid discharged into the ground, and as a result, the strength increases (see, for example, Patent Document 5).
[0006]
[Patent Document 1]
JP 2001-317050 A (FIGS. 1 and 2)
[Patent Document 2]
Japanese Patent Laying-Open No. 2002-201638 (FIG. 2)
[Patent Document 3]
JP 2000-291002 A (FIGS. 1, 2, and [0012])
[Patent Document 4]
Japanese Patent No. 2731806 (FIG. 1f and claim 1)
[Patent Document 5]
Japanese Patent Laying-Open No. 2001-040653 (FIGS. 3 to 5 and claim 1)
[0007]
[Problems to be solved by the invention]
As described above, the solidified material liquid is discharged into the ground with a device having at least a solidified material liquid discharge port in the soil cement column and at least a drilling blade and a stirring blade, and the device is rotated. The steel pipe having a wing portion on the outer peripheral surface at least below in the soil cement column after the solidified cement liquid and the excavated soil are agitated and mixed to build a soil cement column that is an abundant soil cement portion. It was known to bury piles.
[0008]
However, in the conventional method, in order to build a soil cement portion that is rich in solidification material at the lower end portion, that is, a root consolidation portion, a solidification material solution having a concentration higher than the concentration of the solidification material solution discharged when excavating from the ground. We switched to, and were building a solidification part. Therefore, it takes time to switch the solidifying material liquid, and it is necessary to prepare two types of concentrations of the solidifying material liquid, which increases the construction cost.
[0009]
The first object of the present invention is to have a blade on at least the lower outer surface in the soil cement column even if it is constructed by preparing only one kind of solidifying material liquid in order to suppress an increase in construction cost. It is providing the construction method in which the soil cement synthetic | combination pile by which the steel pipe pile was embed | buried can exhibit predetermined support force.
[0010]
Further, in the method of constructing a soil cement composite pile in which a steel pipe pile having a wing portion at least on the lower outer surface is embedded in a soil cement column based on a conventional method, as a steel pipe pile having a wing portion on the lower outer surface The outer diameter D of the wing part is about 1.5 times or more and less than 2.5 times the outer diameter d of the part excluding the wing part and 20 to 70 cm, and the outer diameter d of the part excluding the wing part is 10 to 40 cm. Using a steel pipe pile, the solidified material is discharged by discharging the solidified material liquid into the ground with a device having a discharge port for the solidified material solution at the bottom and at least a drilling blade and a stirring blade, and rotating the device to solidify the material. The soil cement column is excavated to a predetermined ground while stirring and mixing the liquid and the excavated soil, and has an outer diameter of about 1.2 to 2 times the outer diameter D of the wing and 40 to 120 cm in the ground. From the bottom of the soil cement pillar while building As a soil cement composite pile by building a soil cement part rich in solidification material in the range of about 1 to 2 times the outer diameter D of the blade, and then burying it while rotating the steel pipe pile described above, When the N value at the lower end was less than 20, the soil cement composite pile had a supporting force commensurate with the ground. However, although the reason is unknown, when the tip N value is 22 or more, a soil cement synthetic pile capable of expressing a high supporting force corresponding to the ground, that is, the supporting ground, has not been obtained.
[0011]
At this time, even if the work of refining without adding the solidified material liquid discharged into the ground shown in Patent Document 5 described above is applied, if the tip N value becomes 22 or more, the N value of the ground is set. No soil cement composite pile with suitable bearing capacity was obtained.
[0012]
A second object of the present invention is to construct a soil cement pillar having a root portion by digging up to the ground where the tip N value is 22 or more, and at least a wing portion of the above-described size is provided in the lower outer surface. Soil cement composite pile for making a soil cement composite pile capable of expressing a high bearing capacity corresponding to the ground having a tip N value of 22 or more, that is, even if it is a soil cement composite pile by burying a steel pipe pile having It is to provide a method of constructing.
[0013]
[Means for Solving the Problems]
1st invention is the invention described in Claim 1, In the method of constructing the soil cement synthetic | combination pile by which the steel pipe pile which has a wing | blade part at least in the lower outer surface was embedded in the soil cement pillar, it solidified in the lower part. In a device having a material liquid discharge port and having at least an excavating blade and a stirring blade, the solidified material liquid is discharged into the ground and the device is rotated so that the solidified material liquid and the excavated soil are stirred and mixed. After digging to the ground of the soil and building a soil cement column in the ground, the device is pulled up from the bottom of the soil cement column to a range of about 1 to 2 times the outer diameter D of the wing, and then the concentration of the solidified material liquid The soil cement part rich in solidifying material in the range from the lowest part of the soil cement column to the lifting position of the wing part by discharging the solidifying material liquid without changing the level and rotating and lowering the device Were construction, a method of wings of the lower outer surface of the subsequent steel pipe pile is applying a soil cement synthetic pile, characterized by embedding the steel pipe pile to be positioned in rich soil cement portion of the solidifying material.
[0014]
As described above, in the present invention, it is not necessary to change the concentration of the solidifying solution when constructing the soil cement portion rich in the solidifying material. Therefore, only by preparing the solidifying material solution having one concentration, the soil rich in the solidifying material is prepared. A cement cement pile can be built, and a steel pipe pile having a wing portion on the outer surface below is embedded in a soil cement column, and a soil cement composite pile can exhibit a predetermined supporting force.
[0015]
When building the soil cement part rich in solidifying material, by building the soil cement part rich in solidifying material by lowering it at the same speed as the excavation speed, the construction time of the entire soil cement column can be shortened, Moreover, since it is stirred and mixed even when the discharge of the solidifying material liquid is stopped and the apparatus having the discharge port of the solidifying material liquid in the lower part and having the excavating blade and the excavating blade is rotated from the lowest end, it is agitated and mixed. Cement pillars can be built.
[0016]
In addition, the soil cement portion rich in the solidifying material of the present invention is abundant in the solidifying material by two discharges of the solidifying material liquid discharged at the time of the first excavation and the solidifying material liquid discharged at the time of lowering. It becomes a part. Therefore, when descending at the same speed as the speed at the time of excavation, the solid cement-rich soil cement part is because the one kind of solidified liquid prepared for this invention is discharged twice at the same speed. This is a soil cement part in which the amount of the solidifying material is doubled.
[0017]
When the bearing capacity required for the soil cement pile is high depending on the ground, the concentration of the solidifying material liquid to be prepared can be increased. In that case, the upper part of the soil cement column also becomes a soil cement part with a lot of solidified material, but as a result, the strength of the upper soil cement is also increased, and the steel pipe pile with wings on the outer side is also used at the upper part Also, the unity of the upper wing and the soil cement part is enhanced, and a soil cement composite pile having a higher proof strength when a lateral force is applied during an earthquake or the like.
[0018]
As described above, the outer diameter D of the wing portion as a steel pipe pile having the wing portion on at least the lower outer surface is about 1.5 times or more and less than 2.5 times the outer diameter d of the portion excluding the wing portion, and 20 to Using a steel pipe pile with an outer diameter d of about 10 to 40 cm excluding the blade part, which is 70 cm, solidified in an apparatus having a solidified material liquid discharge port at the bottom and an excavation blade and a stirring blade By discharging the material liquid into the ground and rotating the apparatus, the solidified material liquid and the excavated soil are agitated and mixed to the ground where the tip N value is 22 or more, and the outer diameter of the wing part is underground. In the case of a method of constructing a soil cement composite pile in which a soil cement pillar having an outer diameter of about 1.2 to 2 times D and having an outer diameter of 40 cm to 120 cm is constructed and the steel pipe pile is embedded, the soil cement pillar If the strength of the lower part is low, the load of the structure is concentrated on the thin steel pipe pile. Because, destroyed the lower part of the soil cement pillar, high support force can not be expected as a soil cement synthetic pile. Therefore, the solidified material liquid and the excavated soil are stirred and mixed by discharging the solidified material liquid into the ground with a device having a discharge port for the solidified material liquid at the bottom and having a drilling blade and a stirring blade, and rotating the device. While digging to the ground with a tip N value of 22 or more, a soil cement column having an outer diameter of about 1.2 to 2 times the outer diameter D of the wing portion and an outer diameter of 40 cm to 120 cm was built in the ground. Later, the device is pulled up from the bottom of the soil cement column to a range of about 1 to 2 times the outer diameter D of the wing, and then the solidifying material liquid is discharged and the device is rotated without changing the concentration of the solidifying material liquid. As a result, the soil cement part rich in solidification material is built in the range from the lowest part of the soil cement column to the lifting position of the wing part, and then the outer diameter d of the part excluding the wing part of the steel pipe pile is increased. The bottom of the soil cement pillar It is to applying a soil cement synthetic pile by embedding the steel pipe pile positioned above about 20cm about ~30cm from the lower end. Even in this case, the wing portion on the lower outer surface of the steel pipe pile is located in a soil cement portion rich in solidifying material. With such a construction method, even if a thin steel pipe pile is used, the soil cement synthetic pile can exhibit a high bearing capacity commensurate with the ground having a tip N value of 22 or more, that is, the supporting ground.
[0019]
In this case, in order to obtain a higher supporting force, the solidified material in the soil cement portion rich in the solidified material built from the lowermost part to the range of about 1 to 2 times the outer diameter D of the wing portion is in the portion. It is desirable that at least about 500 kg is added per unit volume (1 m 3 ).
[0020]
In any of the above-described inventions, if the steel pipe pile to be used is a steel pipe pile having a wing portion on the lower outer surface and a wing on the outer surface of the upper portion, the upper portion is also integrated with the soil cement pillar. As a result, it becomes a soil cement composite pile having high yield strength not only in the vertical direction but also when a lateral force is applied during an earthquake or the like.
[0021]
Of course, the steel pipe pile to be used may be a pile having a wing portion on the outer side surface of the intermediate portion in addition to the wing portion on the lower outer surface and the upper outer surface.
[0022]
Further, the steel pipe pile used in the present invention may be a joint of several piles. In that case, in the jointed state, there is a wing portion at the lower end of the pile at the lowermost end, and further, What has a wing part in the part close | similar to the ground part of the pile of the piled uppermost end part is called a steel pipe pile which has a wing part on the lower outer surface and has a wing on the outer surface of the upper part in this invention. Moreover, when connecting steel pipe piles, it is preferable from the point of construction to set it as a screw type coupling rather than the connection by welding.
[0023]
In this invention, the tip N value refers to the average value (average N value) of the ground between 1D downward and 1D upward from the tip of the steel pipe pile, and the ground where the tip N value is 22 or more. This average N value refers to the ground of 22 or more. That is, when the protrusion 3e exists at the lower end of the main body 3d of the steel pipe pile, the lowermost end of the steel pipe pile excluding the protrusion 3e is the tip.
[0024]
Next, an example of a method for constructing the soil cement composite pile according to the present invention will be described with reference to the drawings.
[0025]
FIG. 1 is a construction process diagram. As shown in FIG. 2, the soil cement pillar construction apparatus 1 used in FIG. 1 has a solidified material discharge port 1b at a lower portion of a hollow rod 1a. In addition, the apparatus includes an excavating blade 1c and a stirring blade 1d on the outer periphery of the rod 1a, and a co-rotation preventing blade 1e pivotally attached to the rod 1a so that the rotation of the rod 1a is not transmitted. The co-rotation preventing blade 1e has an outer diameter larger than that of the excavating blade 1c and the stirring blade 1d, and the excavated soil stirred by the excavating blade rotates in the same manner as the rotation of the rod, that is, prevents the co-rotation. It is something to do. Further, in this apparatus, a tip excavating blade 1f is provided at the most distal end portion of the rod 1a. However, if the soil cement pillar can be built, an apparatus having a solidifying material liquid discharge port in the lower part and having a drilling blade and a stirring blade can be used as the soil cement pillar building device in the present invention.
[0026]
Moreover, as shown in FIG. 3, the steel pipe pile 3 which has a wing | blade part in the lower outer surface shown in FIG. 1 is a steel pipe pile which has a wing | blade part in the lower outer surface, and the spiral wing | blade part 3a in the illustrated example. It is. In the illustrated example, there are wing portions (spiral wing portions in the illustrated example) 3b and 3c on the upper outer peripheral surface and intermediate outer peripheral surface, and at the lower end of the main portion of the steel pipe pile, that is, the portion 3d excluding the wing. It has a plate-like protrusion 3e. In addition, the lowest end of the main body part (namely, the part except a wing | blade) 3d of the steel pipe pile except this projection part 3e is called the lowest end part of a steel pipe pile. There is no need to have a plate-like protrusion at the tip, in which case the lower end of the steel pipe pile is the lowermost end.
[0027]
The steel pipe pile 3 preferably used in the present invention is a steel pipe pile whose outer diameter D of the wing part is about 1.5 times or more and less than 2.5 times the outer diameter d of the part excluding the wing part and is 20 to 70 cm. It is.
[0028]
The construction process of an example of the method of constructing the soil cement synthetic pile when using the steel cement pile building apparatus 1 of FIG. 3 using the soil cement pillar construction apparatus 1 of FIG. 2 described above is shown in FIG. It is.
[0029]
As shown in FIG. 1 (a), the rod 1a of the soil cement pillar construction device 1 is lowered by a device (not shown) (for example, an auger motor) at a place where the soil cement composite pile 4 is to be constructed, and the discharge port 1b. By discharging a solidified material liquid such as cement milk from the ground, the excavated soil and the solidified material liquid are stirred and mixed by a stirring blade or the like, and a soil cement is built.
[0030]
In addition, when it is desired to have a so-called empty digging portion where the solidifying material liquid is not mixed in the vicinity of the ground surface portion, a solidifying material liquid such as cement milk is passed through the discharge port 1b after passing the empty digging portion. What is necessary is just to discharge.
[0031]
In this way, as shown in FIG. 1 (b), when the soil cement pillar construction device 1 reaches a desired depth, the cement milk from the discharge port 1b of the solidifying liquid such as cement milk from the discharge port 1b. After stopping the discharge of the solidifying material liquid such as, the apparatus 1 is pulled up while rotating the rod to the range of about 1 to 2 times the wing part outer diameter D of the steel pipe pile 3 to be buried. This state is shown in FIG. Thereafter, the apparatus 1 is lowered while rotating while discharging the solidifying material liquid without changing the concentration of the solidifying material liquid. The most lowered state is shown in FIG.
[0032]
Thereafter, the discharge of the solidifying material liquid such as cement milk from the discharge port 1b is stopped, and the rod is rotated and recovered to the ground surface. The state after recovery is shown in FIG. As seen in this figure, a soil cement portion 2a rich in solidifying material is present below the soil cement 2.
[0033]
FIG. 4 shows the state of discharging the solidifying material liquid and the state of not discharging the solidifying material liquid in each step described above, with the elapsed time on the horizontal axis and the depth on the vertical axis. In FIG. 4, a portion indicated by a solid line is a portion where the solidifying material liquid is discharged, and a portion indicated by a broken line is a portion where the solidifying material liquid is not discharged.
[0034]
The concentration of the solidifying material liquid used is the same in any part, and as shown in FIG. 4, the first excavation speed and the second descending speed are the same.
[0035]
As shown in FIG. 1 (f), a steel pipe pile 3 having wings on the lower outer surface is buried while rotating, and as shown in FIG. 1 (g), the wings on the lower outer surface of the steel pipe piles. Is located in the soil cement portion 2a rich in solidifying material.
[0036]
When this soil cement is solidified, the soil cement synthetic pile 4 exhibits a high supporting force.
[0037]
When embedding the steel pipe pile, the distance between the lowermost end part of the outer diameter d of the part excluding the wing part of the steel pipe pile 3 and the lowermost end of the soil cement column, the distance indicated by L1 in FIG. 5 is at least 20 cm to 30 cm. If present to some extent, the support capacity of the soil cement composite pile will exhibit the best performance. Therefore, it is most preferable that the lowermost end portion of the outer diameter d of the portion excluding the wing portion is positioned about 20 cm to 30 cm above the lowermost end of the soil cement column. In addition, the space | interval shown as L2 in FIG. 5 is corresponded to the distance which pulled up the soil cement pillar construction apparatus 1 to the range about 1-2 times the wing | blade part outer diameter D of the steel pipe pile 3 mentioned above.
[0038]
Moreover, the outer diameter of the soil cement pillar to be constructed (diameter indicated as Dc in FIG. 5) is about 1.2 to 2 times the outer diameter D of the wing portion of the steel pipe pile to be used, and 40 cm or more and 120 cm or less. Is most preferred.
[0039]
This is when the steel pipe pile is a steel pipe pile in which the outer diameter D of the wing portion is about 1.5 to 2.5 times the outer diameter d of the portion excluding the wing portion and is 20 to 70 cm. If the diameter of the soil cement column is too large, there is a part that cannot behave integrally with the steel pipe pile, and there is a risk that the performance as a soil cement composite pile will be reduced. This is because it is difficult to obtain a mixed state.
[0040]
In addition, soil cement composite piles with steel pipe piles with wings on the lower outer surface embedded in the soil cement columns exhibit excellent performance by integrating the soil cement and steel pipe piles. It is better to specify the diameter of the steel pipe and the diameter of the wing part in order to achieve the best performance. Even if the ratio between the diameter of the steel pipe pile and the blade diameter is too small or too large, the performance as a soil cement synthetic pile is not sufficiently exhibited.
[0041]
【Example】
Using the apparatus shown in FIG. 2 up to a depth of 5.5 m on the ground shown in FIG. 6, construction was performed in the steps shown in FIGS.
[0042]
That is, as shown in FIGS. 1A to 1B, the rod is rotated, and the excavation is performed while discharging the solidified material liquid so that about 250 kg of solidified material is added per unit volume (1 m 3 ) of the excavated soil. A soil cement pillar having an outer diameter of 700 m was built at a speed of 1.0 m / min, and then the apparatus shown in FIG. 2 was rotated by 0.7 m without discharging the solidifying liquid as shown in FIG. Raised while. Thereafter, as shown in FIG. 1 (d), while rotating the rod, the solidifying material liquid having the same concentration as before is discharged again at a speed of 1.0 m / min, and as shown in FIG. 1 (e), The apparatus shown in FIG. 2 was pulled upward while rotating the rod without discharging the solidifying material liquid.
[0043]
In this way, a portion rich in solidifying material was constructed in the range of 0.7 m. The solidified material in this part is added at least about 500 kg per volume in that part (that is, per 1 m 3 of excavation volume of this part).
[0044]
The tip N value of this ground was 50.
[0045]
With this soil cement column uncured, a steel pipe pile having the shape shown in FIG. 3 was embedded as shown in FIGS. That is, the wing portion on the lower outer surface of the steel pipe pile is positioned in a soil cement portion rich in solidifying material.
[0046]
The steel pipe pile used had an outer diameter D of the wing portion of 500 mm, an outer diameter d of the portion excluding the wing portion of 267.4 mm, and a length of 5.5 m.
[0047]
Moreover, the lower end part of this steel pipe pile was located 200 mm above the lowest end of the soil cement pillar.
[0048]
The soil cement synthetic pile thus constructed was measured for bearing capacity on the 28th day after the construction of the soil cement was cured. The supporting force was 4200 KN.
[0049]
For reference, soil cement composite piles were dug to investigate the strength of the soil cement. The results are shown in FIG. 7, and the strength of the lower soil cement was 8.8 N / mm 2 .
[0050]
In addition, the uniaxial compressive strength of soil cement for every depth was shown in FIG.
[0051]
[Comparative example]
As a comparative example, a soil is formed under the same conditions as in the example, except that the steps (c) and (d) in FIG. 1 are not performed, that is, a portion rich in solidifying material is not built in the lower part. A cement composite pile was constructed. The bearing capacity of this soil cement synthetic pile was 1900KN. For reference, soil cement composite piles were dug to investigate the strength of the soil cement. The result is shown in FIG. 7, and the strength of the lower soil cement was 3.0 N / mm 2 .
[0052]
【The invention's effect】
According to this invention, after the soil cement pillar is built in the ground, the apparatus is pulled up from the lowest part of the soil cement pillar to a range of about 1 to 2 times the outer diameter D of the wing part, and then the concentration of the solidified material liquid Since the soil cement part rich in solidifying material is built in the range from the lowest part of the soil cement column to the lifting position of the wing part by lowering while rotating the device while discharging the solidifying material liquid without changing the The concentration of the solidifying material liquid to be prepared is only one type, and the construction time for constructing a soil cement column having a soil cement portion rich in solidifying material is substantially shortened.
[0053]
In addition, in the range from about 1 to 2 times the outer diameter D of the wing part from the lowest part of the soil cement column built first, the excavated soil and the solidified material liquid are uniformly mixed by the next apparatus pulling up again. Next, the solidified material liquid is further stirred and mixed while the solidified material liquid is further discharged into the soil cement that is made uniform by rotating and lowering the device while discharging the solidified material liquid. Sometimes mixed and stirred again. Therefore, the soil cement portion rich in the solidifying material can be made into a uniform state by sufficiently mixing the excavated soil and the solidifying material liquid.
[0054]
Therefore, since the steel pipe pile is embedded so that the wing portion on the outer surface below the steel pipe pile is located in the soil cement portion rich in solidification material, a soil cement pile having a high supporting force can be obtained. For example, even when the tip of the soil cement is allowed to reach the support ground where the tip N value is 22 or more, the soil cement pile having a high support force corresponding to the support ground can be obtained.
[0055]
Furthermore, when the steel pipe pile is buried so that the lowermost end portion of the outer diameter d of the portion excluding the wing portion of the steel pipe pile is located about 20 cm to 30 cm above the lowermost end of the soil cement column, it is supported by the soil cement synthetic pile. The load of the superstructure is transmitted to the steel pipe pile main body, and is transmitted from the lowermost wing to the support ground. The distance from this wing to the support ground is about 20 cm to 30 cm, and solidifies. Since the soil cement part rich in wood has sufficient strength, it is dispersed and transmitted to the support ground at the bottom of the soil cement, and the soil cement part rich in solidifying material is strong enough due to strong peripheral friction force Demonstrate support. Therefore, the soil cement composite pile can exhibit higher performance.
[Brief description of the drawings]
FIG. 1 is a diagram showing an example of a construction process according to the present invention.
FIG. 2 is a view showing an example of a soil cement pillar construction device used in the present invention.
FIG. 3 is an elevation view and a plan view showing an example of a steel pipe pile used in the present invention.
FIG. 4 is a diagram showing the relationship between the depth at the time of building the soil cement pillar of the present invention and the solidified material discharge state.
FIG. 5 is a view showing a tip portion of a soil cement synthetic pile according to the present invention.
FIG. 6 is a diagram showing a ground condition tested in an example.
FIG. 7 is a graph showing the compressive strength of soil cement.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Soil cement pillar construction apparatus, 2 ... Soil cement, 3 ... Steel pipe pile, 4 ... Soil cement synthetic pile.

Claims (4)

  1. ソイルセメント柱中に少なくとも下方の外側面に翼部を有する鋼管杭が埋設されたソイルセメント合成杭を施工するに際して、下部に固化材液の吐出口を有しかつ掘削翼と攪拌翼を有する装置にて固化材液を地中に吐出すると共にその装置を回転させることにより固化材液と掘削土とを攪拌混合しながら支持層内まで掘進し、地中にソイルセメント柱を築造した後に、ソイルセメント柱の最下部から前記翼部の外径Dの1〜2倍程度の範囲まで装置を引き上げ、その後、固化材液濃度を変えることなく固化材液を吐出しかつ装置を回転しながら、かつ下降させることによりソイルセメント柱の最下部から前記翼部の引き上げ位置までの範囲に固化材の豊富なソイルセメント部分を築造し、その後に鋼管杭の下方の外側面の翼部が固化材の豊富なソイルセメント部分中に位置するように鋼管杭を埋設することを特徴とするソイルセメント合成杭を施工する方法。When constructing a soil cement synthetic pile in which a steel pipe pile having a blade part at least on the lower outer surface is embedded in a soil cement column, an apparatus having a discharge port for a solidifying material liquid at the bottom and an excavation blade and a stirring blade After discharging the solidified material liquid into the ground and rotating the device, the solidified material liquid and the excavated soil are agitated and mixed to the inside of the support layer, and after building the soil cement pillar in the ground, the soil Pull up the device from the lowest part of the cement pillar to a range of about 1 to 2 times the outer diameter D of the wing, then discharge the solidifying material liquid without changing the concentration of the solidifying material liquid and rotate the device, and By lowering, a soil cement part rich in solidification material is built in the range from the lowest part of the soil cement pillar to the lifting position of the wing part, and then the wing part on the lower outer surface of the steel pipe pile is rich in solidification material How to applying a soil cement synthetic pile, characterized by embedding the steel pipe pile to be positioned in the soil cement portion.
  2. ソイルセメント柱中に少なくとも下方の外側面に翼部を有する鋼管杭が埋設されたソイルセメント合成杭を施工するに際して、下方の外側面に翼部を有する鋼管杭として翼部の外径Dが翼部を除く部分の外径dの約1.5倍以上2.5倍未満でかつ20〜70cmであり、翼部を除く部分の外径dが10〜40cmである鋼管杭を使用して、下部に固化材液の吐出口を有しかつ掘削翼と攪拌翼を有する装置にて固化材液を地中に吐出すると共にその装置を回転させることにより固化材液と掘削土とを攪拌混合しながら先端N値が22以上となる地盤まで掘進し、地中に前記翼部の外径Dの1.2倍〜2倍程度でかつ40cm以上120cm以下の外径のソイルセメント柱を築造した後に、ソイルセメント柱の最下部から前記翼部の外径Dの1〜2倍程度の範囲まで装置を引き上げ、その後、固化材液濃度を変えることなく固化材液を吐出しかつ装置を回転しながら下降させることによりソイルセメント柱の最下部から前記翼部の引き上げ位置までの範囲に固化材の豊富なソイルセメント部分を築造し、その後に鋼管杭の翼部を除く部分の外径dの最下端部がソイルセメント柱の最下端から20cm程度〜30cm程度上方に位置するように鋼管杭を埋設することを特徴とするソイルセメント合成杭を施工する方法。When constructing a soil cement composite pile in which a steel pipe pile having a wing part is embedded in at least a lower outer surface in a soil cement column, the outer diameter D of the wing part is a wing part as a steel pipe pile having a wing part on the lower outer surface. Using a steel pipe pile that is about 1.5 times to less than 2.5 times the outer diameter d of the portion excluding the portion and 20 to 70 cm, and the outer diameter d of the portion excluding the wing portion is 10 to 40 cm, The solidified material liquid and the excavated soil are stirred and mixed by discharging the solidified material liquid into the ground with a device having a discharge port for the solidified material liquid at the bottom and having a drilling blade and a stirring blade, and rotating the device. However, after digging to the ground where the tip N value is 22 or more, and building a soil cement column having an outer diameter of about 1.2 to 2 times the outer diameter D of the wing and 40 cm or more and 120 cm or less in the ground From the bottom of the soil cement column, the outer diameter D of the wing part is 1 Pull up the device to a range of about twice, then discharge the solidifying material liquid without changing the concentration of the solidifying material liquid and lower it while rotating the device from the bottom of the soil cement column to the lifting position of the wing part A soil cement portion rich in solidifying material is built in the range of, and then the lowermost end portion of the outer diameter d of the portion excluding the wing portion of the steel pipe pile is positioned about 20 cm to 30 cm above the lowermost end of the soil cement column. A method of constructing a soil cement synthetic pile characterized by burying a steel pipe pile.
  3. 最下部から前記翼部の外径Dの1〜2倍程度の範囲までに築造する固化材の豊富なソイルセメント部分における固化材が該部分における体積当たり500kg程度添加されていることを特徴とする請求項2記載のソイルセメント合成杭を施工する方法。About 500 kg of solidified material is added in the soil cement portion rich in solidified material to be built from the lowest part to the range of about 1 to 2 times the outer diameter D of the wing portion. A method for constructing the soil cement composite pile according to claim 2.
  4. 使用する鋼管杭が、下方の外側面に翼部を有すると共に、上方部の外側面に翼を有する鋼管杭であることを特徴とする請求項1から3記載のソイルセメント合成杭を施工する方法。4. The method for constructing a soil cement composite pile according to claim 1, wherein the steel pipe pile to be used is a steel pipe pile having a wing portion on a lower outer surface and a wing portion on an outer surface of the upper portion. .
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JP4664157B2 (en) * 2005-09-01 2011-04-06 旭化成建材株式会社 Construction method of bladed steel pipe pile and soil cement composite pile
CN102704470A (en) * 2012-06-20 2012-10-03 宫能和 Mixing pile blade
EP3121339B1 (en) * 2014-03-19 2019-10-30 Asahi Kasei Construction Materials Corporation Steel pipe with spiral blades, composite pile, and construction method of composite pile
CN104594342B (en) * 2014-12-31 2016-08-24 宗超 Cam SMW engineering method stake machine
CN104863133A (en) * 2015-06-05 2015-08-26 张璐 One-time forming equipment for combined pile
CN104863136A (en) * 2015-06-05 2015-08-26 宋姝娴 Method for executing oval pile manufacturing device
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CN107178080A (en) * 2016-09-14 2017-09-19 北京荣创岩土工程股份有限公司 Soil cement is combined pre-threaded stake and its pile making method
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