JP2004339747A

JP2004339747A - Injection method of grout into existing structure foundation ground and its device

Info

Publication number: JP2004339747A
Application number: JP2003136085A
Authority: JP
Inventors: Takeshi Miyamoto; 武司宮本
Original assignee: Shimizu Construction Co Ltd; Shimizu Corp
Current assignee: Shimizu Construction Co Ltd; Shimizu Corp
Priority date: 2003-05-14
Filing date: 2003-05-14
Publication date: 2004-12-02
Anticipated expiration: 2023-05-14
Also published as: JP4092644B2

Abstract

<P>PROBLEM TO BE SOLVED: To provide an injection method of grout into the existing structure foundation ground injecting the grout suitable for ground improvement in the foundation ground under the existing structure without causing harmful variation in the existing structure and its device. <P>SOLUTION: When the grout 15 suitable for ground improvement by using an injection means 2 for the foundation ground 13, the foundation ground 13 and variations in a foundation floor slab 9 of the existing structure 8 are monitored by making use of a variation detecting means 3 to properly adjust injection pressure and, at the same time, the pumping of ground water 14 is carried out by making use of a pumping means 6 so that the groundwater-head of the foundation ground 13 can be stored within a predetermined range in parallel with these operations to carry out the ground improvement of the foundation ground 13 without causing harmful variation in the existing structure 8. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明は、既存構造物下の基礎地盤に、地盤改良に好適な注入液を注入する既存構造物基礎地盤への注入液の注入方法及び装置に関する。
【０００２】
【従来の技術】
従来より、軟弱地盤上に立地する重要構造物では、地震時の地盤液状化対策が必要とされており、その有力な対策工法として薬液注入工法がある。薬液注入工法では、薬液を地盤中に加圧注入するため、注入孔の近傍地盤や近接構造物を変状させる場合が多い。このため、特許文献１に示すように、長時間をかけて極低圧力下で、かつ大口径の注入改良体を造成できる注入方法が考案されている。
【０００３】
【特許文献１】
特開２００２−３１７４３６号公報
【０００４】
【発明が解決しようとする課題】
しかし、このような構成においても、図８に示すように、止水壁１６や粘性土層等の不透水性障壁で囲まれた既存構造物１７下の基礎地盤１８に、薬液１９を注入する場合には、注入量に見合うだけの地下水２０の逃げ場がないため、注入対象である基礎地盤１８の水圧が上昇しやすく、既存構造物１７の基礎床版２１やこれに取り付く壁２２に、傾斜や撓み等の変位が生じたり、亀裂や漏水が生じる等、構造物や機械設備としての機能に不具合を生じさせる場合が多い。このため、既存構造物１７に不具合を生じさせないような既存構造物１７下の基礎地盤１８に対する地盤改良に好適な注入液の注入工法が求められている。
【０００５】
上記事情に鑑み、本発明は、既存構造物に有害な変状を生じさせることなく、既存構造物下の基礎地盤に、地盤改良に好適な注入液を注入する既存構造物基礎地盤への注入液の注入方法及び装置を提供することを目的としている。
【０００６】
【課題を解決するための手段】
請求項１記載の既存構造物基礎地盤への注入液の注入方法は、既存構造物下の基礎地盤に、地盤改良に好適な注入液を注入する既存構造物基礎地盤への注入液の注入方法であって、前記既存構造物の基礎床版を貫通し、基礎地盤の所定深さに達する複数の鉛直孔を設置する第１の工程と、何れか１体の鉛直孔を前記注入液の注入孔、これと隣接する複数の鉛直孔を揚水孔と位置付ける第２の工程と、前記注入孔周辺における基礎床版、及び基礎地盤の変状状況をモニタリングし、変状量が所定限度に収まるように注入圧力を制御しながら、前記注入孔から基礎地盤へ注入液を注入するとともに、これと並行して前記揚水孔から地下水を揚水し、地下水頭が所定範囲に収まるように制御する第３の工程とにより構成され、前記鉛直孔すべてに対して、第２の工程及び第３の工程を繰り返すことを特徴としている。
【０００７】
請求項２記載の既存構造物基礎地盤への注入液の注入装置は、既存構造物下の基礎地盤に、地盤改良に好適な注入液を注入する既存構造物基礎地盤への注入液の注入装置であって、前記基礎地盤に、前記注入液を加圧注入する注入手段と、前記基礎地盤、及び既存構造物の基礎床版に係る変状状況を検知する変状検知手段と、前記基礎地盤中の地下水を揚水する揚水手段と、前記変状検知手段及び注入手段に連動し、変状検知手段から基礎地盤及び基礎床版の変状量を通知され、変状状況に応じて基礎地盤への注入液の最適な注入圧力量を算定し、該注入圧力量を注入手段に通知する計測演算手段を備えてなり、前記変状検知手段に、基礎床版の変状及び損傷を検知する床版変状検知手段、及び基礎地盤の水分量変化及び表面の漏水を検知する基礎地盤変状検知手段を備えることを特徴としている。
【０００８】
請求項３記載の既存構造物基礎地盤への注入液の注入装置は、前記注入手段に、基礎地盤への注入液の注入圧力量を自動制御する注入圧力制御機構が備えられることを特徴としている。
【０００９】
請求項４記載の既存構造物基礎地盤への注入液の注入装置は、前記変状検知手段の基礎地盤変状検知手段に、基礎地盤に接触することなく水分量変化及び表面の漏水を把握する非接触式隔測型のセンサが備えられることを特徴としている。
【００１０】
請求項５記載の既存構造物基礎地盤への注入液の注入装置は、前記揚水手段が、圧縮空気を生成するコンプレッサと、該コンプレッサより生成された圧縮空気を基礎地盤中に設置された揚水孔に送気する送気管と、前記揚水孔に一端を挿入される揚水管を備えてなり、前記送気管を介して送気された圧縮空気の押圧力を利用して、基礎地盤中の地下水を揚水管を介して揚水することを特徴としている。
【００１１】
請求項６記載の既存構造物基礎地盤への注入液の注入装置は、前記揚水手段に、前記基礎地盤中の地下水頭を検知する液面センサと、該液面センサ及び前記コンプレッサに連動する地下水頭制御機構を備えており、前記地下水頭制御装置が、液面センサから通知された水頭レベルに応じて、前記地下水の揚水量を制御することを特徴としている。
【００１２】
【発明の実施の形態】
本発明の既存構造物基礎地盤への注入液の注入方法及び装置は、基礎地盤に地盤改良に好適な注入液を注入するに際し、基礎地盤及び既存構造物の基礎床版の変状をモニタリングして、適宜注入圧力を調整するとともに、これらと並行して基礎地盤の地下水頭が所定範囲内に収まるよう揚水を実施することにより、既存構造物に有害な変形を生じさせることなく、基礎地盤の地盤改良を実施するものである。
【００１３】
図１に示すように、既存構造物の基礎地盤への注入液の注入装置１は、注入手段２と、変状検知手段３と、揚水手段６と、計測演算手段７を備えている。前記注入手段２は、地盤改良に好適な薬液等の注入液１５を、基礎地盤１３に加圧注入するものであり、本実施の形態では、注入圧力を制御することの可能な、注入圧力制御機構２ｃを備えた構成を有している。
一般に、一定速度での地盤への注入液１５の注入は、注入速度と注入圧力の関係が、図２のグラフに示すように非線形である。したがって、注入速度を減少させても、一概に注入圧力が低下するとは限らないため、注入速度の変更を介して、地盤への注入液１５の注入圧力量を調整する方法は、作業が繁雑である。以下、簡略に注入圧力量を調整できる注入圧力制御機構２ｃを備えた注入手段２を示す。
【００１４】
図１に示すように、該注入手段２は、注入液１５を加圧した状態で貯留している加圧槽２ａ、加圧槽２ａ内を加圧するためのコンプレッサ２ｂ、加圧槽２ａの内圧を制御することで、注入液１５の注入圧力量を制御する注入圧力制御機構２ｃ、加圧槽２ａに注入液１５を補給するための補給装置２ｄ、及び注入液１５を基礎地盤１３に注入する注入ホース２ｈを備えている。また、前記補給装置２ｄには、補給制御器２ｆ、液量検出器２ｇ、及び補給用の注入液１５を貯留する貯液槽２ｅが備えられている。
前記加圧槽２ａに付設されている注入圧力制御機構２ｃは、加圧槽２ａ内の液位を所望の圧力に維持するように補給装置２ｄを制御して注入液１５の補給を行うとともに、加圧槽２ａ内の液位が下がることに伴う圧力低下や、注入液１５の補給に伴う加圧槽２ａ内の圧力上昇を検知して、コンプレッサ２ｂを制御して加圧槽２ａ内の圧力を常に一定に保持するように制御するものである。
【００１５】
つまり、注入手段２は、上記のように加圧槽２ａの圧力を注入圧力制御機構２ｃにより一定に保持しつつ、加圧槽２ａ内の注入液１５を注入ホース２ｈを介して基礎地盤１３に連続的に加圧注入することにより、一定流量の注入液１５を一定速度で注入するものである。また、基礎地盤１３への注入圧力量は、注入圧力制御機構２ｃにより制御される加圧槽２ａ内の圧力により決定される。したがって、注入圧力量は、加圧槽２ａ内の液位を所望の圧力に維持することのできる注入圧力制御機構２ｃにより容易に調整でき、該加圧槽２ａ内の圧力を維持することで、注入液１５を基礎地盤１３へ所望の注入圧力量を維持した状態で、安定にかつ連続的に注入することができるものである。
なお、該注入手段２は、必ずしも上述する構成にこだわるものではなく、一定流量の注入液１５を一定速度で基礎地盤１３に連続的に加圧注入することが可能であり、また、注入加圧ｐを調整できるものであれば、何れを用いても良い。
【００１６】
また、前記変状検知手段３は、注入手段２を用いて注入液１５を基礎地盤１３に注入する際に、前記既存構造物８の基礎床版９、及び基礎地盤１３に生じると想定される変状を検知するもので、前記既存構造物８における基礎床版９の変状や損傷を検知する床版変状検知手段４と、既存構造物８下の基礎地盤１３の水分量変化や表面の漏水を検知する基礎地盤変状検知手段５を備えている。
【００１７】
前記床版変状検知手段４は、図３に示すように、前記基礎床版９に関して、水平軸に対する傾斜、撓みを検知する傾斜計４ａ、ひずみセンサ４ｂ、隆起や沈下等の面外方向の変位を検知する変位センサ４ｃ、面上に生じた亀裂等を検知する画像センサ４ｄ、及び生じた亀裂の長さや幅を検知する距離センサ４ｅ等を備えている。
【００１８】
一方、前記基礎地盤変状検知手段５は、図４に示すように、基礎地盤１３に関して、含水量を検知する水分センサ５ａ、ｐＦセンサ５ｂ、静電容量・電気抵抗センサ５ｃ、及び熱映像センサ５ｄを備えている。本実施の形態において、水分センサ５ａには、電磁波の減衰状態から基礎地盤１３中の水分量を検知する赤外線吸収やマイクロ波吸収等の電磁波吸収型を採用している。また、ｐＦセンサ５ｂは、一般に土壌水、つまり土壌に一定の圧力をかけたときに取り出せる水の状態を表す指標として用いられているｐＦを検知するものであり、ｐＦ測定値から図５に示すような、基礎地盤１８の水分特性曲線をもとに水分量の変化を把握するものである。
【００１９】
これら水分センサ５ａ及びｐＦセンサ５ｂは、基礎地盤１３中に露出するように配置する接触型のセンサであるが、前記静電容量・電気抵抗センサ５ｃ、及び熱映像センサ５ｄは、基礎地盤１３が表面を被覆されている場合にも作動する非接触式隔測型のセンサである。静電容量・電気抵抗センサ５ｃは、水分量に応じて鋭敏に変化する静電容量または電気抵抗を指標として含水量の変化を把握するものであり、熱映像センサ５ｄは、基礎地盤１３中の水分量を温度分布変化として測定し、一度に広範囲な領域の水分量変化を推定できるものである。
【００２０】
このように、基礎地盤１３の水分量変化や表面の漏水を検知する基礎地盤変状検知手段５に、接触型だけでなく非接触式隔測型のセンサを備える構成は、前記既存構造物８の基礎床版９だけでなく、その他コンクリート、アスファルト、防水層等により、基礎地盤１３の表面が被覆された状態においても、基礎地盤１３の変状を的確に把握することを目的とするものである。
【００２１】
上述する構成の前記変状検知手段３は、前記注入手段２により基礎地盤１３に注入液１５を注入した際に生じると想定される前記基礎床版９及び基礎地盤１３の様々な変状状況を検知し、前記計測演算手段７に通知する。
該計測演算手段７は、前記変状検知手段３より通知された計測データより、基礎床版９及び基礎地盤１３の変状状況に応じて最適な注入液１５の注入圧力量を算定し、計測演算手段７に連動している注入手段２に、この最適な注入圧力量を通知するものである。
なお、先にも述べたように、本実施の形態では、注入手段２が注入液１５の注入圧力量を自動制御することの可能な注入圧力制御機構２ｃを備えていることから、該注入圧力制御機構２ｃを介して注入液１５の注入圧力量を、計測演算手段７により通知された注入圧力量に自動制御できるが、注入手段２に注入圧力制御機構２ｃを有しない場合には、注入手段２に別途注入圧力を調整する制御機構を備える構成とすればよい。
【００２２】
ところで、前記注入装置１には、図１に示すように、さらに揚水手段６が備えられている。該揚水手段６は、前記注入手段２を介して基礎地盤１３に注入液１５を注入することにより、基礎地盤１３から押し出された地下水１４を揚水するものであり、これにより、基礎地盤１３の地下水頭を一定の範囲内に保持するものである。
前記揚水手段６は、図１に示すように、前記基礎地盤１３の所定位置に設けられた揚水孔１１に一端を挿入され、地下水１４を地上に揚水する揚水管６ａ、揚水孔１１に送気管６ｂを介して圧縮空気を送気するコンプレッサ６ｃ、前記送気管６ｂに備えられ、圧縮空気を送気及び遮断する電磁弁６ｅを備えるとともに、前記揚水孔１１に挿入され、基礎地盤１３中の地下水頭を把握する液面センサ６ｆ、該液面センサ６ｆ及び前記電磁弁６ｅに連動しており、揚水孔１１への圧縮空気の送気及び遮断を制御することにより地下水１４の揚水量を制御する地下水頭制御機構６ｄを備えている。
【００２３】
上述する構成の揚水手段６は、例えば、前記液面センサ６ｆを介して地下水頭が所定の範囲より上昇したことを検知すると、前記地下水頭制御機構６ｄを介して電磁弁６ｅが開放され、コンプレッサ６ｃから送気管６ｂを介して圧縮空気が揚水孔１１に供給される。地下水１４は、圧縮空気により揚水管６ａを介して地上に揚水されるため、揚水ポンプ等を設置する必要がない。また、揚水により地下水頭が所定の範囲内に収まった場合には、前記地下水頭制御機構６ｄは液面センサ６ｆを介して地下水頭が所定の範囲内に収まったことを検知し、前記地下水頭制御機構６ｄを介して電磁弁６ｅが遮断され、揚水孔１１への圧縮空気の供給が中断されることに伴い、揚水管６ａによる地下水の揚水も中断される。
なお、近接位置に揚水孔１１を複数設け、該揚水孔１１各々から地下水を揚水したい場合にも、前記コンプレッサ６ｃに揚水孔１１と同数の送気管６ｂを設けて、複数の揚水孔１１各々に該送気管６ｂ及び揚水管６ａを備える構成とすれば良く、複数の揚水孔１１各々に揚水ポンプを設ける必要はない。
【００２４】
上述する構成の注入装置１を用いて、既存構造物１７下の基礎地盤１３への注入液１５を注入する、既存構造物基礎地盤の注入方法を以下に示す。
【００２５】
（第１の工程）
まず、第１の工程として、図６に示すように、前記既存構造物８下の基礎地盤１３に対して、注入液１５を注入することを目的に、前記基礎床版９を貫通し、基礎地盤１３の所定深さに達する鉛直孔１０を、所定の離間間隔をもって複数構築する。
【００２６】
（第２の工程）
次に、第２の工程として、何れか１つの鉛直孔１０を前記注入液１５の注入孔１２、これと隣接する他の鉛直孔１０を揚水孔１１と位置付け、前記注入装置１を設置する。該注入装置１の設置は、図１に示すように、前記注入孔１２に注入手段２、前記揚水孔１１に揚水手段６、さらに、注入孔１２近傍に変状検知手段３を配置することによる。
なお、変状検知手段３を配置する際に、接触型のセンサである前記水分センサ５ａ及びｐＦセンサ５ｂは、基礎地盤１３中が露出している場所に配置する、また、非接触式の隔測センサである前記静電容量・電気抵抗センサ５ｃ、及び熱映像センサ５ｄは、注入孔１２近傍の所定範囲を検知できるように設置する。
【００２７】
（第３の工程）
この後、第３の工程として、図７に示すように、前記注入孔１２周辺における基礎床版９、及び基礎地盤１３の変状状況を変状検知手段３を介してモニタリングし、変状量が所定限度に収まるように注入圧力量を制御しながら、前記注入手段２を介して注入孔１２から基礎地盤１３へ注入液１５を注入する。
一方で、前記揚水手段６の液面センサ６ｆを用いて、基礎地盤１３中の地下水頭の変動をモニタリングし、地下水頭が所定範囲より上昇した際には、揚水手段６を介して地下水１４を揚水することにより、地下水頭が所定範囲に収まるように制御する。
【００２８】
例えば、基礎地盤１３へ注入液１５を注入作業中、基礎床版９に亀裂が生じる等の損傷が発生し、噴発や漏水等が生じた際には、図４に示すように、該損傷箇所に前記接触型のセンサである前記水分センサ５ａ及びｐＦセンサ５ｂを再配置するとともに、亀裂等損傷箇所の形状及びその近接領域を、図３に示すように、床版変状検知手段４を介して把握し、前記計測演算手段７にて基礎床版９及び基礎地盤１３の変状や損傷が許容範囲内であるかを判定する。許容範囲外と判定された場合には、基礎地盤１３への注入液１５の注入圧力量の最適値を算定し、計測演算手段７から注入手段２に注入圧力量の最適値を通知する。このように、注入圧力量を制御しながら所定量の注入液１５を基礎地盤１３へ注入する。
【００２９】
基礎床版９に備えられた複数の鉛直孔１０すべてを順に注入孔１２とし、第２の工程、及び第３の工程を繰り返すことにより、前記既存構造物下の基礎地盤全域に注入液を注入し、地盤改良を終了する。
【００３０】
上述する構成によれば、基礎地盤１３に地盤改良に好適な注入液１５を注入するに際し、基礎地盤１３及び既存構造物１７の基礎床版９の変状を、モニタリングして、適宜注入圧力を調整するとともに、これらと並行して基礎地盤１３の地下水頭が所定範囲内に収まるよう揚水を実施することから、注入液１５の注入に伴う基礎地盤１３中の過剰水圧や、過剰水圧に伴う既存構造物８の基礎床版９や基礎床版９に取り付く壁等の損傷を防止することができ、既存構造物１７に有害な変状を生じさせることなく、精度良い基礎地盤１３の地盤改良を実施することが可能となる。
【００３１】
前記注入装置１は、変状検知手段３を備えていることから、既存構造物１７下の基礎地盤１３に地盤改良に好適な注入液１５を注入しながら、既存構造物１７の基礎床版９に生じやすい隆起や沈下等の面外方向の変位や傾斜、撓み、亀裂等の変状、及び基礎地盤１３の水分量変化や表面の漏水等を、常時精度良くモニタリングすることができるため、早期のうちに基礎床版９もしくは基礎地盤１３の変状の兆候を検知することができ、変状状況に応じてきめ細かで、精度良い注入液１５に係る注入圧力制御を実施することが可能となる。
これにより、既存構造物１７の近傍においても隣接構造物に有害な変状を生じさせることなく、精度の良い前記基礎地盤１３への注入が可能となる。
【００３２】
また、前記注入装置１に備えられた注入手段２には、注入圧力制御機構２ｃが備えられていることから、これまで煩雑であった注入圧力量の調整を容易に実施することができ、作業効率を大幅に向上することが可能になるとともに、施工精度を大幅に向上することが可能となる。
【００３３】
さらに、前記注入装置１に備えられた変状検知手段３には、基礎地盤１３の水分量変化及び表面の漏水を検知することの可能な非接触型の隔測センサが備えられることから、前記基礎地盤１３の表面が被覆されているような目視が不可能な状況においても、前記基礎地盤１３の変状を的確に把握することが可能となり、変状状況に応じてきめ細かで、精度良い注入圧力制御を実施することが可能となる。
【００３４】
また、前記注入装置１に備えられた揚水手段６には、圧縮空気を生成するコンプレッサ６ｃが備えられており、圧縮空気を揚水孔１１に送気することにより、押圧力で地下水１４を揚水する構成を備えていることから、従来より一般に用いられていた揚水ポンプを不要とするため、設備及び配管に係る作業やコストを大幅に削減することが可能となる。
このような構成は、複数の揚水孔１１を用いる場合にも、これと同数の送気管６ｂをコンプレッサ６ｃに備え付け、該送気管６ｂ及び揚水管６ａを複数の揚水孔１１各々に挿入させればよく、地下水１４の揚水作業をより効率的で低コストに実施することが可能となる。
【００３５】
上述する揚水手段６には、地下水頭を検知する前記液面センサ６ｆと、該液面センサ６ｆからの通知をもとに、地下水１４の揚水量を制御する地下水頭制御機構６ｄを備えることから、地下水頭を所定範囲に制御しながら容易に揚水することができ、過剰揚水による基礎地盤の陥没や沈下等の変状を防止することが可能になるとともに、運転動力の省エネ化も図ることが可能となる。
【００３６】
【発明の効果】
請求項１記載の既存構造物基礎地盤への注入液の注入方法によれば、既存構造物下の基礎地盤に、地盤改良に好適な注入液を注入する既存構造物基礎地盤への注入液の注入方法であって、前記既存構造物の基礎床版を貫通し、基礎地盤の所定深さに達する複数の鉛直孔を設置する第１の工程と、何れか１体の鉛直孔を前記注入液の注入孔、これと隣接する複数の鉛直孔を揚水孔と位置付ける第２の工程と、前記注入孔周辺における基礎床版、及び基礎地盤の変状状況をモニタリングし、変状量が所定限度に収まるように注入圧力を制御しながら、前記注入孔から基礎地盤へ注入液を注入するとともに、これと並行して前記揚水孔から地下水を揚水し、地下水頭が所定範囲に収まるように制御する第３の工程とにより構成され、前記鉛直孔すべてに対して、第２の工程及び第３の工程を繰り返す。
これにより、注入液の注入に伴う基礎地盤中の過剰水圧や、過剰水圧に伴う既存構造物の基礎床版や、基礎床版に取り付く壁等の損傷を防止することができ、既存構造物に有害な変状を生じさせることなく、精度良い基礎地盤の地盤改良を実施することが可能となる。
【００３７】
請求項２記載の既存構造物基礎地盤への注入液の注入装置によれば、既存構造物下の基礎地盤に、地盤改良に好適な注入液を注入する既存構造物基礎地盤への注入液の注入装置であって、前記基礎地盤に、前記注入液を加圧注入する注入手段と、前記基礎地盤、及び既存構造物の基礎床版に係る変状状況を検知する変状検知手段と、前記基礎地盤中の地下水を揚水する揚水手段と、前記変状検知手段及び注入手段に連動し、変状検知手段から基礎地盤及び基礎床版の変状量を通知され、変状状況に応じて基礎地盤への注入液の最適な注入圧力量を算定し、該注入圧力量を注入手段に通知する計測演算手段を備えてなり、前記変状検知手段に、基礎床版の変状及び損傷を検知する床版変状検知手段、及び基礎地盤の水分量変化及び表面の漏水を検知する基礎地盤変状検知手段を備える。
これにより、既存構造物下の基礎地盤に地盤改良に好適な注入液を注入する際に、既存構造物の基礎床版に生じやすい隆起や沈下等の面外方向の変位や傾斜、撓み、亀裂等の変状、及び基礎地盤の水分量変化や表面の漏水等を、常時精度良くモニタリングすることができるため、早期のうちに基礎床版もしくは基礎地盤の変状の兆候を検知することができ、変状状況に応じてきめ細かで、精度良い注入液に係る注入圧力制御を実施することが可能となる。
また、既存構造物の近傍においても隣接構造物に有害な変状を生じさせることなく、精度の良い前記基礎地盤への注入が可能となる。
【００３８】
請求項３記載の既存構造物基礎地盤への注入液の注入装置によれば、前記注入手段に、基礎地盤への注入液の注入圧力量を自動制御する注入圧力制御機構が備えられる。
これにより、これまで煩雑であった注入圧力の調整を容易に実施することができ、作業効率を大幅に向上することが可能になるとともに、施工精度を大幅に向上することが可能となる。
【００３９】
請求項４記載の既存構造物基礎地盤への注入液の注入装置によれば、前記変状検知手段の基礎地盤変状検知手段に、基礎地盤に接触することなく水分量変化及び表面の漏水を把握する非接触式隔測型のセンサが備えられる。
これにより、前記基礎地盤の表面が被覆されているような目視が不可能な状況においても、前記基礎地盤の変状を的確に把握することが可能となり、変状状況に応じてきめ細かで、精度良い注入圧力制御を実施することが可能となる。
【００４０】
請求項５記載の既存構造物基礎地盤への注入液の注入装置によれば、前記揚水手段が、圧縮空気を生成するコンプレッサと、該コンプレッサより生成された圧縮空気を基礎地盤中に設置された揚水孔に送気する送気管と、前記揚水孔に一端を挿入される揚水管を備えてなり、前記送気管を介して送気された圧縮空気の押圧力を利用して、基礎地盤中の地下水を揚水管を介して揚水する。
これにより、従来より一般に用いられていた揚水ポンプを不要とするため、設備及び配管に係る作業やコストを大幅に削減することが可能となる。
このような構成は、複数の揚水孔を用いる場合にも、これと同数の送気管をコンプレッサに備え付け、該送気管及び揚水管を複数の揚水孔各々に挿入させればよく、地下水の揚水作業をより効率的で低コストに実施することが可能となる。
【００４１】
請求項６記載の既存構造物基礎地盤への注入液の注入装置によれば、前記揚水手段に、前記基礎地盤中の地下水頭を検知する液面センサと、該液面センサ及び前記コンプレッサに連動する地下水頭制御機構を備えており、前記地下水頭制御装置が、液面センサから通知された水頭レベルに応じて、前記地下水の揚水量を制御する。
これにより、地下水頭を所定範囲に制御しながら容易に揚水することができ、過剰揚水による基礎地盤の陥没や沈下等の変状を防止することが可能になるとともに、運転動力の省エネ化も図ることが可能となる。
【図面の簡単な説明】
【図１】本発明に係る既存構造物基礎地盤への注入液の注入装置の概略を示す図である。
【図２】本発明に係る注入液の注入圧力と注入速度の関係を示すグラフである。
【図３】本発明に係る変状検知手段に備えられた床版変状検知手段の詳細を示す図である。
【図４】本発明に係る変状検知手段に備えられた基礎地盤変状検知手段の詳細を示す図である。
【図５】本発明に係る土壌水分特性曲線を示す図である。
【図６】本発明に係る既存構造物の基礎床版に設置された鉛直孔の配置状況を示す図である。
【図７】本発明に係る既存構造物基礎地盤への注入液の注入方法を示す図である。
【図８】従来の既存構造物基礎地盤への注入液の注入方法を示す図である。
【符号の説明】
１注入装置
２注入手段
２ａ加圧層
２ｂコンプレッサ
２ｃ注入圧力制御機構
２ｄ補給装置
２ｅ貯液層
２ｆ補給制御器
２ｇ液量検出器
２ｈ注入ホース
３変状検知手段
４床版変状検知手段
４ａ傾斜計
４ｂひずみセンサ
４ｃ変位センサ
４ｄ画像センサ
４ｅ距離センサ
５基礎地盤変状検知手段
５ａ水分センサ
５ｂｐＦセンサ
５ｃ静電容量・電気抵抗センサ
５ｄ熱映像センサ
６揚水手段
６ａ揚水管
６ｂ送気管
６ｃコンプレッサ
６ｄ地下水頭制御機構
６ｅ電磁弁
６ｆ液面センサ
７計測演算手段
８既存構造物
９基礎床版
１０鉛直孔
１１揚水孔
１２注入孔
１３基礎地盤
１４地下水
１５注入液
１６止水壁
１７既存構造物
１８基礎地盤
１９薬液
２０地下水
２１基礎床版
２２壁[0001]
TECHNICAL FIELD OF THE INVENTION
TECHNICAL FIELD The present invention relates to a method and an apparatus for injecting an injection liquid into an existing structure foundation ground for injecting an injection liquid suitable for ground improvement into a foundation ground below the existing structure.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, important structures located on soft ground have been required to take measures against ground liquefaction during an earthquake, and there is a chemical solution injection method as an effective countermeasure method. In the chemical solution injection method, a chemical solution is injected under pressure into the ground, so that the ground near the injection hole and the adjacent structure are often deformed. For this reason, as shown in Patent Document 1, an injection method has been devised in which a large-diameter injection-improved body can be formed under extremely low pressure over a long period of time.
[0003]
[Patent Document 1]
JP-A-2002-317436
[0004]
[Problems to be solved by the invention]
However, even in such a configuration, as shown in FIG. 8, the chemical solution 19 is injected into the foundation ground 18 under the existing structure 17 surrounded by the impermeable barrier such as the water blocking wall 16 and the cohesive soil layer. In such a case, since there is no escape for the groundwater 20 corresponding to the injection amount, the water pressure of the foundation ground 18 to be injected is likely to increase, and the base floor 21 of the existing structure 17 and the wall 22 attached thereto are inclined. In many cases, the function as a structure or mechanical equipment is inferior, for example, displacement such as deformation or bending, cracking or water leakage is generated. For this reason, there is a need for a method of injecting an injection liquid suitable for soil improvement for the foundation ground 18 under the existing structure 17 so as not to cause a problem in the existing structure 17.
[0005]
In view of the above circumstances, the present invention provides an injection into an existing structure foundation ground in which an injection liquid suitable for ground improvement is injected into the foundation ground under the existing structure without causing harmful deformation to the existing structure. It is an object of the present invention to provide a method and an apparatus for injecting a liquid.
[0006]
[Means for Solving the Problems]
The method for injecting an injection liquid into an existing structure foundation ground according to claim 1 is a method for injecting an injection liquid suitable for ground improvement into an existing structure foundation ground below an existing structure. A first step of piercing a foundation slab of the existing structure and installing a plurality of vertical holes reaching a predetermined depth of the foundation ground, and injecting any one of the vertical holes with the injection liquid Hole, a second step of positioning a plurality of vertical holes adjacent to the hole as a pumping hole, and monitoring the deformation state of the foundation slab and the foundation ground around the injection hole, so that the deformation amount falls within a predetermined limit. Injecting the injection liquid from the injection hole into the foundation ground while controlling the injection pressure at the same time, pumping the groundwater from the pumping hole in parallel with this, and controlling the groundwater head to fall within a predetermined range. Process for all the vertical holes. Te is characterized by repeating the second and third steps.
[0007]
An injection device for injecting liquid into an existing structure foundation ground according to claim 2, wherein the injection liquid suitable for ground improvement is injected into the foundation ground below the existing structure. An injection means for pressurizing and injecting the injection liquid into the foundation ground, a deformation detection means for detecting a deformation state of the foundation ground, and a base slab of an existing structure, and the base ground In conjunction with the pumping means for pumping groundwater inside, and the deformation detection means and the injection means, the deformation detection means is notified of the deformation amount of the foundation ground and the foundation slab, and to the foundation ground according to the deformation state. Calculating an optimal injection pressure amount of the injection liquid of the above, and measuring and calculating means for notifying the injection pressure amount to the injection means, wherein the deformation detection means detects the deformation and damage of the base slab. Plate deformation detection means, and detects changes in the moisture content of the foundation ground and water leakage on the surface It is characterized in that it comprises a foundation ground deformation detecting means.
[0008]
According to a third aspect of the present invention, there is provided an apparatus for injecting an injection liquid into an existing structure foundation ground, wherein the injection means is provided with an injection pressure control mechanism for automatically controlling an injection pressure amount of the injection liquid into the foundation ground. .
[0009]
The injection device for injecting liquid into the existing structure foundation ground according to claim 4, wherein the base ground deformation detection means of the deformation detection means grasps a change in water content and surface leakage without contacting the base ground. It is characterized in that a non-contact type distance measurement type sensor is provided.
[0010]
6. The apparatus for injecting a liquid to be injected into a foundation ground of an existing structure according to claim 5, wherein the pumping means is configured to generate a compressed air and a pumping hole provided in the base ground for the compressed air generated by the compressor. An air supply pipe for supplying air to the pump, and a water supply pipe having one end inserted into the water pumping hole, and using the pressing force of the compressed air supplied through the air supply pipe, groundwater in the foundation ground is removed. It is characterized by pumping water through a pumping pipe.
[0011]
7. The apparatus for injecting an injection liquid into an existing structure foundation ground according to claim 6, wherein the pumping means includes a liquid level sensor for detecting a groundwater head in the foundation ground, and a groundwater interlocked with the liquid level sensor and the compressor. A head control mechanism is provided, wherein the groundwater head control device controls the pumping amount of the groundwater in accordance with the head level notified from a liquid level sensor.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
The method and apparatus for injecting the injection liquid into the existing structure foundation ground of the present invention monitors the deformation of the foundation ground and the foundation slab of the existing structure when injecting the injection liquid suitable for ground improvement into the foundation ground. In addition to adjusting the injection pressure as appropriate, pumping water so that the groundwater head of the foundation ground falls within a predetermined range in parallel with these, without causing harmful deformation of the existing structure, This is to improve the ground.
[0013]
As shown in FIG. 1, an apparatus 1 for injecting an injection liquid into the foundation ground of an existing structure includes an injection unit 2, a deformation detection unit 3, a pumping unit 6, and a measurement calculation unit 7. The injection means 2 is for injecting an injection liquid 15 such as a chemical solution suitable for ground improvement into the base ground 13 under pressure. In the present embodiment, the injection pressure control is capable of controlling the injection pressure. It has a configuration provided with a mechanism 2c.
Generally, when the injection liquid 15 is injected into the ground at a constant speed, the relationship between the injection speed and the injection pressure is non-linear as shown in the graph of FIG. Therefore, even if the injection speed is reduced, the injection pressure does not always decrease. Therefore, the method of adjusting the injection pressure amount of the injection liquid 15 to the ground through the change of the injection speed is complicated. is there. Hereinafter, the injection unit 2 including the injection pressure control mechanism 2c capable of simply adjusting the injection pressure amount will be described.
[0014]
As shown in FIG. 1, the injection means 2 includes a pressurized tank 2a storing the injected liquid 15 in a pressurized state, a compressor 2b for pressurizing the pressurized tank 2a, and an internal pressure of the pressurized tank 2a. , The injection pressure control mechanism 2 c for controlling the injection pressure amount of the injection liquid 15, the replenishing device 2 d for replenishing the injection tank 15 with the injection liquid 15, and the injection liquid 15 is injected into the base ground 13. An injection hose 2h is provided. Further, the replenishing device 2d is provided with a replenishment controller 2f, a liquid amount detector 2g, and a liquid storage tank 2e for storing a replenishing liquid 15 for replenishment.
The injection pressure control mechanism 2c attached to the pressurized tank 2a controls the replenishing device 2d to maintain the liquid level in the pressurized tank 2a at a desired pressure, and replenishes the injected liquid 15, The compressor 2b is controlled by detecting a pressure drop due to a decrease in the liquid level in the pressurizing tank 2a and a pressure increase in the pressurizing tank 2a due to the replenishment of the injection liquid 15, and controlling the pressure in the pressurizing tank 2a. Is always controlled to be constant.
[0015]
In other words, the injection means 2 keeps the pressure of the pressurized tank 2a constant by the injection pressure control mechanism 2c as described above, and transfers the injected liquid 15 in the pressurized tank 2a to the foundation ground 13 via the injection hose 2h. By injecting continuously under pressure, an infusion liquid 15 having a constant flow rate is injected at a constant speed. The injection pressure amount to the foundation ground 13 is determined by the pressure in the pressurized tank 2a controlled by the injection pressure control mechanism 2c. Therefore, the injection pressure amount can be easily adjusted by the injection pressure control mechanism 2c that can maintain the liquid level in the pressurized tank 2a at a desired pressure, and by maintaining the pressure in the pressurized tank 2a, The injection liquid 15 can be stably and continuously injected into the foundation ground 13 while maintaining a desired injection pressure amount.
The injection means 2 is not necessarily limited to the above-described configuration, and can inject the injection liquid 15 at a constant flow rate at a constant speed into the foundation ground 13 under pressure. Any one can be used as long as p can be adjusted.
[0016]
It is assumed that the deformation detecting means 3 is generated in the base slab 9 of the existing structure 8 and the base ground 13 when the injection liquid 15 is injected into the base ground 13 using the injection means 2. A slab deformation detecting means 4 for detecting deformation and detecting deformation or damage of the foundation slab 9 in the existing structure 8, and a change in water content or surface of the foundation ground 13 under the existing structure 8 Is provided with a ground deformation detecting means 5 for detecting a ground leakage.
[0017]
As shown in FIG. 3, the floor slab deformation detecting means 4 includes an inclinometer 4a for detecting inclination and bending of the base slab 9 with respect to a horizontal axis, a strain sensor 4b, and an out-of-plane direction It is provided with a displacement sensor 4c for detecting displacement, an image sensor 4d for detecting a crack or the like generated on a surface, a distance sensor 4e for detecting the length or width of the generated crack, and the like.
[0018]
On the other hand, as shown in FIG. 4, the foundation ground deformation detecting means 5 includes a moisture sensor 5a for detecting the water content, a pF sensor 5b, a capacitance / electric resistance sensor 5c, and a thermal image sensor for the foundation ground 13. 5d. In the present embodiment, the moisture sensor 5a employs an electromagnetic wave absorption type such as infrared absorption or microwave absorption that detects the amount of water in the base ground 13 from the attenuation state of the electromagnetic wave. The pF sensor 5b detects pF, which is generally used as an index indicating the state of soil water, that is, water that can be taken out when a certain pressure is applied to soil, and is shown in FIG. The change in the amount of water is grasped based on such a water characteristic curve of the foundation ground 18.
[0019]
The moisture sensor 5a and the pF sensor 5b are contact-type sensors arranged so as to be exposed in the foundation ground 13, but the capacitance / electric resistance sensor 5c and the thermal image sensor 5d have the foundation ground 13 This is a non-contact type remote sensor that operates even when the surface is coated. The capacitance / electric resistance sensor 5c is for grasping a change in water content by using an index of capacitance or electric resistance that changes sharply according to the amount of moisture as an index. By measuring the amount of water as a change in the temperature distribution, it is possible to estimate a change in the amount of water in a wide range at a time.
[0020]
As described above, the configuration provided with not only the contact type but also the non-contact type separation type sensor in the basic ground deformation detecting means 5 for detecting the change in the water content of the basic ground 13 and the leakage of the surface is the same as that of the existing structure 8. The purpose of the present invention is to accurately grasp the deformation of the foundation ground 13 even when the surface of the foundation ground 13 is covered with not only the base slab 9 but also other concrete, asphalt, a waterproof layer, and the like. .
[0021]
The deformation detecting means 3 having the above-described configuration detects various deformation states of the base slab 9 and the base ground 13 which are assumed to be generated when the injection liquid 2 is injected into the base ground 13 by the injection means 2. It detects and notifies the measurement calculation means 7.
The measurement calculation means 7 calculates the optimum injection pressure amount of the injection liquid 15 according to the deformation state of the foundation slab 9 and the foundation ground 13 from the measurement data notified from the deformation detection means 3 and performs measurement. The optimum injection pressure amount is notified to the injection means 2 linked to the calculation means 7.
As described above, in the present embodiment, since the injection means 2 includes the injection pressure control mechanism 2c capable of automatically controlling the injection pressure amount of the injection liquid 15, the injection pressure is controlled. The injection pressure amount of the injection liquid 15 can be automatically controlled via the control mechanism 2c to the injection pressure amount notified by the measurement / calculation means 7, but if the injection means 2 does not have the injection pressure control mechanism 2c, the injection means 2 may be provided with a control mechanism for separately adjusting the injection pressure.
[0022]
By the way, as shown in FIG. 1, the injection device 1 is further provided with water pumping means 6. The pumping means 6 pumps the groundwater 14 extruded from the base ground 13 by injecting the injection liquid 15 into the base ground 13 via the injection means 2, and thereby, the groundwater in the base ground 13 It keeps the head within a certain range.
As shown in FIG. 1, the pumping means 6 has one end inserted into a pumping hole 11 provided at a predetermined position of the foundation ground 13, and a pumping pipe 6 a for pumping groundwater 14 to the ground and an air supply pipe to the pumping hole 11. A compressor 6c for sending compressed air through the 6b, an electromagnetic valve 6e provided for the air supply pipe 6b to send and shut off compressed air, and is inserted into the pumping hole 11 and groundwater in the foundation ground 13 The level sensor 6f for grasping the head, which is linked to the level sensor 6f and the solenoid valve 6e, controls the amount of groundwater 14 pumped by controlling the supply and cutoff of compressed air to the pumping hole 11. A groundwater head control mechanism 6d is provided.
[0023]
When the pumping means 6 having the above-described configuration detects, for example, that the groundwater head has risen above a predetermined range via the liquid level sensor 6f, the electromagnetic valve 6e is opened via the groundwater head control mechanism 6d, and the compressor Compressed air is supplied from 6c to the pumping hole 11 via the air supply pipe 6b. Since the groundwater 14 is pumped to the ground by the compressed air via the pumping pipe 6a, it is not necessary to install a pump or the like. When the groundwater head falls within a predetermined range due to pumping, the groundwater head control mechanism 6d detects that the groundwater head has fallen within the predetermined range via the liquid level sensor 6f, and The electromagnetic valve 6e is shut off via the control mechanism 6d, and the supply of the compressed air to the pumping hole 11 is interrupted, so that the pumping of the groundwater by the pumping pipe 6a is also interrupted.
In addition, when a plurality of pumping holes 11 are provided in the proximity position and it is desired to pump groundwater from each of the pumping holes 11, the same number of air supply pipes 6b as the pumping holes 11 are provided in the compressor 6c, and each of the plurality of pumping holes 11 is provided. What is necessary is just to make it the structure provided with the said air supply pipe 6b and the water pumping pipe 6a, and it is not necessary to provide a water pump in each of several pumping holes 11.
[0024]
A method for injecting the existing structure foundation ground in which the injection liquid 1 is injected into the foundation ground 13 below the existing structure 17 using the injection device 1 having the above-described configuration will be described below.
[0025]
(First step)
First, as shown in FIG. 6, as shown in FIG. 6, in order to inject the injection liquid 15 into the foundation ground 13 below the existing structure 8, the foundation floor slab 9 is penetrated, and A plurality of vertical holes 10 reaching a predetermined depth of the ground 13 are constructed at predetermined intervals.
[0026]
(Second step)
Next, as a second step, any one of the vertical holes 10 is positioned as the injection hole 12 of the injection liquid 15 and the other vertical hole 10 adjacent thereto is the pumping hole 11, and the injection device 1 is installed. The injection device 1 is installed by disposing an injection means 2 in the injection hole 12, a pumping means 6 in the water pumping hole 11, and a deformation detecting means 3 near the injection hole 12, as shown in FIG. .
When arranging the deformation detecting means 3, the moisture sensor 5a and the pF sensor 5b, which are contact sensors, are arranged in a place where the foundation ground 13 is exposed. The capacitance / electric resistance sensor 5c and the thermal image sensor 5d, which are sensors, are installed so that a predetermined range near the injection hole 12 can be detected.
[0027]
(Third step)
Thereafter, as a third step, as shown in FIG. 7, the deformation state of the foundation slab 9 and the foundation ground 13 around the injection hole 12 is monitored via the deformation detection means 3, and the deformation amount is measured. The injection liquid 15 is injected from the injection hole 12 into the foundation ground 13 via the injection means 2 while controlling the injection pressure amount so that the pressure falls within a predetermined limit.
On the other hand, the fluctuation of the groundwater head in the foundation ground 13 is monitored using the liquid level sensor 6f of the water pumping means 6, and when the groundwater head rises from a predetermined range, the groundwater 14 is pumped through the water pumping means 6. By pumping the water, the groundwater head is controlled to fall within a predetermined range.
[0028]
For example, during the operation of injecting the injection liquid 15 into the foundation ground 13, damage such as cracking of the foundation slab 9 occurs, and when eruption or water leakage occurs, as shown in FIG. The moisture sensor 5a and the pF sensor 5b, which are the contact-type sensors, are rearranged at the location, and the shape of the damage location such as a crack and the area near the location are changed to the floor slab deformation detection means 4 as shown in FIG. Then, the measurement / calculation means 7 determines whether the deformation or damage of the base slab 9 and the base ground 13 is within an allowable range. When it is determined that the pressure is outside the allowable range, the optimum value of the injection pressure amount of the injection liquid 15 into the foundation ground 13 is calculated, and the measurement calculation unit 7 notifies the injection unit 2 of the optimum value of the injection pressure amount. In this way, a predetermined amount of the injection liquid 15 is injected into the base ground 13 while controlling the injection pressure amount.
[0029]
By pouring all the plurality of vertical holes 10 provided in the base slab 9 into the pouring holes 12 in order and repeating the second step and the third step, the pouring liquid is poured into the entire foundation ground under the existing structure. Then, the ground improvement is completed.
[0030]
According to the above-described configuration, when the injection liquid 15 suitable for ground improvement is injected into the base ground 13, the deformation of the base ground 13 and the base slab 9 of the existing structure 17 is monitored, and the injection pressure is appropriately adjusted. In addition to the adjustment, since the pumping is performed so that the groundwater head of the foundation ground 13 falls within a predetermined range in parallel with the above, the excess water pressure in the foundation ground 13 due to the injection of the injection liquid 15 and the existing water pressure due to the excess water pressure It is possible to prevent damage to the base slab 9 of the structure 8 and the walls attached to the base slab 9 and to improve the ground of the base ground 13 with high accuracy without causing harmful deformation to the existing structure 17. It can be implemented.
[0031]
Since the injection device 1 includes the deformation detecting means 3, the injection slab 15 of the existing structure 17 is injected into the base ground 13 under the existing structure 17 while injecting the injection liquid 15 suitable for ground improvement. It is possible to constantly and accurately monitor out-of-plane displacements such as uplift and subsidence, inclination, deflection, deformation such as cracks, and changes in water content and surface leakage of the foundation ground 13, which are likely to occur at an early stage. Of the base slab 9 or the foundation ground 13 can be detected during the operation, and it is possible to control the injection pressure of the injection liquid 15 in a fine and precise manner according to the state of the deformation. .
Accordingly, even in the vicinity of the existing structure 17, the injection into the foundation ground 13 can be performed with high accuracy without causing harmful deformation of the adjacent structure.
[0032]
Further, since the injection means 2 provided in the injection device 1 is provided with the injection pressure control mechanism 2c, the adjustment of the injection pressure amount, which has been complicated so far, can be easily performed. Efficiency can be greatly improved, and construction accuracy can be significantly improved.
[0033]
Furthermore, since the deformation detecting means 3 provided in the injection device 1 is provided with a non-contact type distance measuring sensor capable of detecting a change in the amount of water in the foundation ground 13 and water leakage on the surface, Even in a situation where the surface of the ground 13 is not visible, such as being covered, the deformation of the foundation ground 13 can be accurately grasped, and the injection pressure is fine and precise according to the deformation state. Control can be performed.
[0034]
Further, the pumping means 6 provided in the injection device 1 is provided with a compressor 6c for generating compressed air, and pumps the groundwater 14 with a pressing force by sending the compressed air to the pumping hole 11. The provision of the configuration eliminates the need for a pump generally used in the past, so that the work and cost related to equipment and piping can be significantly reduced.
With such a configuration, even when a plurality of pumping holes 11 are used, the same number of air supply pipes 6b are provided in the compressor 6c, and the air supply pipes 6b and the pumping pipes 6a are inserted into each of the plurality of pumping holes 11. The work of pumping the groundwater 14 can be performed more efficiently and at low cost.
[0035]
The pumping means 6 described above is provided with the liquid level sensor 6f for detecting the groundwater head, and a groundwater head control mechanism 6d for controlling the pumping amount of the groundwater 14 based on the notification from the liquid level sensor 6f. In addition, it is possible to easily pump water while controlling the groundwater head within a predetermined range, to prevent deformation such as sinking or subsidence of the foundation ground due to excessive pumping, and to save energy for operating power. It becomes possible.
[0036]
【The invention's effect】
According to the method for injecting the injection liquid into the existing structure foundation ground according to claim 1, the injection liquid into the existing structure foundation ground in which the injection liquid suitable for ground improvement is injected into the foundation ground below the existing structure. A filling method, wherein a first step of piercing a foundation slab of the existing structure and installing a plurality of vertical holes reaching a predetermined depth of a foundation ground; Injection hole, a second step of positioning a plurality of vertical holes adjacent thereto as pumping holes, and monitoring the state of deformation of the foundation slab and the foundation ground around the injection hole, the amount of deformation to a predetermined limit While injecting the injection liquid from the injection hole to the foundation ground while controlling the injection pressure so as to fit, the groundwater is pumped from the pumping hole in parallel with this, and the groundwater head is controlled to fall within a predetermined range. And the vertical hole Respect, repeated second and third steps.
As a result, it is possible to prevent excess water pressure in the foundation ground due to the injection of the injection liquid, damage to the foundation slab of the existing structure due to the excess water pressure, and damage to the walls attached to the foundation slab. The ground improvement of the foundation ground with high accuracy can be performed without causing harmful deformation.
[0037]
According to the injection device for injecting liquid into the existing structure foundation ground according to claim 2, the injection liquid into the existing structure foundation ground in which the injection liquid suitable for ground improvement is injected into the foundation ground under the existing structure. An injection device, an injection means for pressurizing and injecting the injection liquid into the base ground, a deformation detection means for detecting a deformation state of the base ground, and a base slab of an existing structure, In conjunction with the pumping means for pumping groundwater in the foundation ground, the deformation detection means and the injection means, the deformation detection means is notified of the amount of deformation of the foundation ground and the base slab, and the base is changed according to the deformation state. It is provided with a measuring and calculating means for calculating an optimum injection pressure amount of the injection liquid to the ground and notifying the injection pressure amount to the injection means, wherein the deformation detecting means detects deformation and damage of the base slab. Floor slab deformation detection means, and changes in moisture content in the foundation ground and surface leakage It provided with the basic ground deformation detection means for knowledge.
Thereby, when injecting the injection liquid suitable for the ground improvement into the foundation ground under the existing structure, displacement, inclination, bending, cracking, and the like in the out-of-plane direction such as a swelling or subsidence that is likely to occur in the foundation slab of the existing structure. Since it is possible to constantly and accurately monitor the deformation of the ground, the change in the moisture content of the foundation ground, the leakage of water on the surface, etc., it is possible to detect signs of the deformation of the foundation slab or foundation ground at an early stage. In addition, it is possible to precisely and precisely control the injection pressure of the injection liquid according to the state of deformation.
In addition, even in the vicinity of the existing structure, accurate injection into the foundation ground can be performed without causing harmful deformation of the adjacent structure.
[0038]
According to the third aspect of the present invention, the injection means is provided with an injection pressure control mechanism for automatically controlling an injection pressure amount of the injection liquid into the foundation ground.
This makes it possible to easily adjust the injection pressure, which has been complicated so far, so that the working efficiency can be greatly improved and the construction accuracy can be greatly improved.
[0039]
According to the injection device for injecting liquid into the existing structure base ground according to claim 4, the base ground deformation detection means of the deformation detection means detects a change in water content and surface leakage without contacting the base ground. A non-contact type sensor for grasping is provided.
This makes it possible to accurately grasp the deformation of the foundation ground even in a situation where visual observation is impossible such that the surface of the foundation ground is covered. Good injection pressure control can be performed.
[0040]
According to the injection device for injecting the injected liquid into the existing structure foundation ground according to claim 5, the pumping means is provided with the compressor for generating the compressed air and the compressed air generated by the compressor in the foundation ground. An air supply pipe for supplying air to the water pumping hole, and a water pumping pipe having one end inserted into the water pumping hole is provided. Pump groundwater through pumping pipes.
This eliminates the need for a pump generally used in the past, so that the work and cost related to equipment and piping can be significantly reduced.
With such a configuration, even when a plurality of pumping holes are used, the same number of air supply pipes may be provided in the compressor, and the air supply pipes and the pumping pipes may be inserted into each of the plurality of pumping holes. Can be implemented more efficiently and at lower cost.
[0041]
According to the injection device for injecting liquid into the existing structure foundation ground according to claim 6, the pumping means is interlocked with a liquid level sensor for detecting a groundwater head in the foundation ground, and the liquid level sensor and the compressor. A groundwater head control mechanism, and the groundwater head control device controls the pumping amount of the groundwater according to the head level notified from a liquid level sensor.
As a result, the groundwater head can be easily pumped while being controlled within a predetermined range, and it is possible to prevent deformation such as sinking or subsidence of the foundation ground due to excessive pumping, and to save energy for operating power. It becomes possible.
[Brief description of the drawings]
FIG. 1 is a view schematically showing a device for injecting an injection liquid into an existing structure foundation ground according to the present invention.
FIG. 2 is a graph showing a relationship between an injection pressure and an injection speed of an injection liquid according to the present invention.
FIG. 3 is a diagram showing details of a floor slab deformation detecting means provided in the deformation detecting means according to the present invention.
FIG. 4 is a view showing details of a foundation ground deformation detecting means provided in the deformation detecting means according to the present invention.
FIG. 5 is a diagram showing a soil moisture characteristic curve according to the present invention.
FIG. 6 is a view showing the arrangement of vertical holes installed on a foundation slab of an existing structure according to the present invention.
FIG. 7 is a view showing a method for injecting an injection liquid into the existing structure foundation ground according to the present invention.
FIG. 8 is a view showing a conventional method of injecting an injection liquid into the existing structure foundation ground.
[Explanation of symbols]
1 injection device
2 Injection means
2a Pressure layer
2b compressor
2c Injection pressure control mechanism
2d replenishing device
2e reservoir
2f Supply controller
2g liquid level detector
2h injection hose
3 Deformation detection means
4 Floor slab deformation detection means
4a Inclinometer
4b strain sensor
4c Displacement sensor
4d image sensor
4e Distance sensor
5 Ground deformation detection means
5a Moisture sensor
5b pF sensor
5c Capacitance and electric resistance sensor
5d thermal image sensor
6 Pumping means
6a Pumping pipe
6b air pipe
6c compressor
6d Groundwater head control mechanism
6e solenoid valve
6f Liquid level sensor
7 Measurement calculation means
8 Existing structures
9 Basic slab
10 vertical holes
11 Pumping hole
12 Injection hole
13 Foundation Ground
14 Groundwater
15 Injection
16 Water stop wall
17 Existing structures
18 Foundation Ground
19 Chemical solution
20 groundwater
21 Basic slab
22 walls

Claims

A method of injecting an injection liquid into an existing structure foundation ground in which an injection liquid suitable for ground improvement is injected into a foundation ground under the existing structure,
A first step of piercing a foundation slab of the existing structure and installing a plurality of vertical holes reaching a predetermined depth of the foundation ground;
A second step of positioning any one of the vertical holes as an injection hole for the injection liquid, and positioning a plurality of vertical holes adjacent thereto as a pumping hole;
While monitoring the deformation state of the foundation slab around the injection hole and the foundation ground, and controlling the injection pressure so that the amount of deformation falls within a predetermined limit, while injecting the injection liquid from the injection hole into the base ground. A third step of pumping groundwater from the pumping hole in parallel with this, and controlling the groundwater head to fall within a predetermined range,
A method for injecting an injection liquid into an existing structure foundation ground, wherein the second step and the third step are repeated for all the vertical holes.

An injection device for injecting liquid into an existing structure foundation ground for injecting an injecting liquid suitable for ground improvement into the foundation ground under the existing structure,
Injection means for injecting the injection solution under pressure into the foundation ground,
Deformation detection means for detecting the state of deformation of the foundation ground, and the foundation slab of the existing structure,
Pumping means for pumping groundwater in the foundation ground,
In conjunction with the deformation detection means and the injection means, the deformation detection means is notified of the amount of deformation of the foundation ground and the foundation slab, and the optimum injection pressure amount of the injection liquid into the base ground according to the deformation state. Calculating, and measuring and calculating means for notifying the injection pressure amount to the injection means, wherein the deformation detection means includes floor slab deformation detection means for detecting deformation and damage of the base slab, and An injection device for injecting liquid into an existing structure base ground, comprising: a base ground deformation detecting means for detecting a change in water content and a surface leak.

In the injection device of the injection liquid into the existing structure foundation ground according to claim 2,
An injection pressure control mechanism for automatically controlling an injection pressure amount of the injection liquid into the foundation ground, wherein the injection means is provided with an injection liquid injection apparatus into the existing structure base ground.

The injection device for injecting liquid into the existing structure foundation ground according to claim 2 or 3,
An existing structure foundation characterized in that the foundation deformation detection means of the deformation detection means is provided with a non-contact type distance measurement type sensor that grasps a change in water content and water leakage on the surface without contacting the foundation ground. A device for injecting liquid into the ground.

An injection device for injecting liquid into the existing structure foundation ground according to any one of claims 2 to 4,
A pump for generating compressed air, an air supply pipe for supplying compressed air generated by the compressor to a pumping hole installed in a foundation ground, and a pumping tube having one end inserted into the pumping hole Equipped with
Utilizing the pressing force of the compressed air sent through the air supply pipe, injecting the injection liquid into the existing structure foundation ground, characterized by pumping groundwater in the foundation ground through a pumping pipe. .

The injection device for injecting liquid into the existing structure foundation ground according to claim 5,
The pumping means includes a liquid level sensor for detecting a groundwater head in the foundation ground, and a groundwater head control mechanism linked to the liquid level sensor and the compressor.
The above-mentioned underground head control device controls the pumping amount of the underground water according to the head level notified from a liquid level sensor, and the injection device for the injection liquid into the existing structure foundation ground.