JP4228339B2 - Mud production system and method for drilling mud - Google Patents

Description

【０１１２】
次に、上述したメタクリル酸ナトリウム(a-1)及びアクリル酸ナトリウム（a-2）と、１０種類の不飽和カルボン酸エステル（b-1〜b-10）とを組み合わせて共重合体（ｘ）（以下、実施例１〜１６）を作製したときの組成比率、モノエステルの含有割合（％）及び数平均分子量を表２に示す。なお、数平均分子量の測定条件を以下に示す。
【０１１３】

【０１１４】
【表２】

【０１１５】
上述した実施例１〜１６の掘削泥水用泥膜形成剤を製造するにあたっては、まず、反応容器に、水３６３部、イソプロピルアルコール１９６部を仕込み、窒素置換した後、８０゜Ｃまで昇温し、攪拌下、メタクリル酸１５１部（１．７５７モル）、メトキシポリエチレングリコール（エチレンオキサイド付加モル数２８）メタクリレート４８部（０．０３６モル）を混合したものと、過硫酸ナトリウム５％水溶液３９．８部（過硫酸ナトリウム０．００８モル）を同時に３時間かけて滴下し反応させた。さらに、同温度で２時間熟成した後、イソプロピルアルコールを蒸留により除き、水酸化ナトリウム４８％水溶液１４６部（水酸化ナトリウム１．７５７モル）で中和した後、固形分３０％になる量の水を加えて数平均分子量４２８００の共重合体（実施例１）を得た。さらに、表２に示した構成単位となるように単量体組成を代え、実施例１と同様にして実施例２〜１６を得た。
【０１１６】
このようにして製造した実施例１〜１６の掘削泥水用泥膜形成剤を泥水に添加し、その造壁性及び泥水粘度を調べた（表３）。
【０１１７】
ここで、掘削泥水用泥膜形成剤を添加する前の泥水については、細粒分７５μｍ以下、比重が１．０５となるように濃度調整して作製した。ちなみに、そのときの粘度は１１．１ mPa・sであった。泥水粘度はＢ型粘度計にて測定した。
【０１１８】
また、同表における造壁性は、ＡＰＩ規格でいうところの指標とは若干異なり、濾水プロセスを促進させて実験時間を短縮させるべく、濾紙の下側を減圧状態とした場合の濾水量として計測したものであり、５ｍｌ以下が良好な造壁性の目安とされる。なお、従来技術と比較すべく、ＣＭＣを用いた場合を比較例１として併せて示した。
【０１１９】
【表３】

【０１２０】
同表でわかるように、実施例１〜６、１１〜１６は、添加量にかかわらず、造壁性が５ｍｌ以下といずれも良好であるとともに、泥水粘度についても低粘性を維持している、言い換えれば良好な分散性が維持されているのに対し、実施例７〜１０では、添加量が少ないときに造壁性が低下していることがわかる。
【０１２１】
ちなみに、ＣＭＣを使った比較例１では、造壁性は確保できるものの、粘度が高くなってしまうという問題点を裏付ける結果となった。
【０１２２】
次に、上述した実施例１１に係る掘削泥水用泥膜形成剤を掘削泥水用分散剤とともに泥水に加えて本実施形態に係る掘削用泥水を作製し、その耐セメント性について実験した。なお、掘削泥水用分散剤としては、上述したＳＳ―Ｂ及び炭酸ナトリウムの二種類を使用し、それぞれを単独に掘削泥水用泥膜形成剤と併用した場合と、両方を掘削泥水用泥膜形成剤と併用した場合について調べた。
【０１２３】
実験結果を図４及び図５に示す。
【０１２４】
まず、上述した掘削用泥水にセメントを添加しない場合の実験結果を図４に示す。同図に示すように、掘削泥水用泥膜形成剤の添加量が０．２５％程度以上になると、掘削泥水用泥膜形成剤を単独で使用した場合（黒丸で示したケース）と掘削泥水用泥膜形成剤に掘削泥水用分散剤を併用した場合（黒丸以外の３ケース）との間で造壁性にほとんど差がないことがわかる。
【０１２５】
次に、上述した掘削用泥水にセメントを１％添加した場合と５％添加した場合の実験結果を図５(a)、(b)に示す。これらの図に示すように、掘削泥水用泥膜形成剤に掘削泥水用分散剤を併用した場合（黒丸以外の３ケース）では、掘削泥水用泥膜形成剤を０．１〜０．２％添加すれば所要の造壁性が得られるのに対し、掘削泥水用泥膜形成剤を単独で使用した場合（黒丸で示したケース）では、掘削泥水用泥膜形成剤をセメント１％の場合には０．３％弱、セメント５％の場合には０．５％添加しなければ所要の造壁性が得られないことがわかる。
【０１２６】
（第２実施形態）
【０１２７】
次に、第２実施形態に係る掘削用泥水の作泥システム及び方法について説明する。なお、第１実施形態と実質的に同一の部品等については同一の符号を付してその説明を省略する。
【０１２８】
すなわち、第２実施形態に係る掘削用泥水の作泥システムも第１実施形態で説明した掘削用泥水の作泥システム１と同様、解膠された掘削土砂を作製する解膠機としての圧密式ミキサー２と、該圧密式ミキサーによって解膠された掘削土砂と清水とが混練された泥水を貯留する泥水槽３と、該泥水槽内の泥水が移送貯留される泥水貯留槽４と、該泥水貯留槽４内に貯留された泥水に添加される掘削泥水用泥膜形成剤及び掘削泥水用分散剤が貯留された貯留タンク６と、炭酸ナトリウム水溶液が貯留された貯留タンク７と、清水槽８と、混合槽９とから概ね構成してあり、掘削泥水用泥膜形成剤及び掘削泥水用分散剤の化学組成が異なる点以外は、第１実施形態に係る掘削用泥水の作泥システムと構成が全く同一であり、したがって、これ以上の詳細な説明は、ここでは省略する。
【０１２９】
本実施形態で用いる掘削泥水用泥膜形成剤は、不飽和カルボン酸及び／又はその塩（ａ）を主構成単位とする（共）重合体（ｘ′）としての単一重合体からなり、該単一重合体の重量平均分子量Ｍｗを２０万〜３００万としてある。
【０１３０】
ここで、単一重合体の重量平均分子量Ｍｗを２０万〜３００万としたのは、重量平均分子量Ｍｗが２０万を下回ると、造壁性の指標である濾水量が５ｍｌをやや上回り、３００万を超えると、濾水量が５ｍｌを大幅に上回るからである。
【０１３１】
なお、濾水量は、ＡＰＩ規格でいうところの指標とは若干異なり、濾水プロセスを促進させて実験時間を短縮させるべく、濾紙の下側を減圧状態にして計測したものであり、５ｍｌ以下が良好な造壁性の目安とされる。
【０１３２】
図６は、本実施形態に係る掘削泥水用泥膜形成剤の一例を示した化学構造式（化学式）であり、不飽和カルボン酸及び／又はその塩（ａ）をアクリル酸ナトリウム６２で構成してなる掘削泥水用泥膜形成剤６１を示してある。
【０１３３】
重量平均分子量Ｍｗの下限値及び上限値は、後述する実験で得られた結果をプロットし、次いでこれらの結果を近似する曲線を作成し、該曲線と濾水量が５ｍｌであるラインとの交点としてそれぞれ２０万、３００万と定めたが、実験誤差等を勘案した経験的な安全率を見込んだ上での重量平均分子量Ｍｗの範囲は、５０万乃至２５０万とするのが望ましい。
【０１３４】
一方、掘削泥水用泥膜形成剤６１は、濃度が２０乃至３０質量％のものを泥水に添加して使用するのが好ましいが、かかる濃度範囲では、重量平均分子量Ｍｗが１００万を超えると、水飴程度の高粘度（１００万mPa・s）となり、泥水に添加するにあたって必ずしも作業性に優れるとは言い難い。
【０１３５】
したがって、かかる添加作業性の観点で掘削泥水用泥膜形成剤６１の重量平均分子量Ｍｗを５０万乃至１００万とするのが望ましい。さらには、濾水量上限を余裕をもってクリアするとともに泥水への添加作業を確実に高めるべく、掘削泥水用泥膜形成剤６１の重量平均分子量Ｍｗを６０万乃至８０万とするのが最適である。
【０１３６】
次に、本実施形態で用いる掘削泥水用分散剤は、ポリアクリル酸塩、ポリメタクリル酸塩若しくはそれらの共重合体であってその重量平均分子量Ｍｗを１００００乃至１４０００としたものであれば、その組成等は任意であり、例えば、重量平均分子量Ｍｗが１００００乃至１４０００であるポリアクリル酸のナトリウム塩から構成することが可能である。具体的には、ＳＵＰＥＲ ＳＬＲＲＹ Ｂ（三洋化成工業株式会社製）の商品名で市販されているポリカルボン酸系安定液用分散剤（以下、単にＳＳ―Ｂと呼ぶ）を使用することができる。また、かかるＳＳ−Ｂに代えて、又はそれに加えて炭酸ナトリウムを用いることもできる。
【０１３７】
本実施形態に係る掘削用泥水の作泥システムを用いて掘削用泥水を作製するには、まず、解膠前の掘削土砂を、他の現場からの搬入や当該現場の用地内でのバックホウやバケット式のケリー掘削機などによる掘削によって調達する。
【０１３８】
なお、地中連続壁工法や泥水シールド工法では、土砂分離装置やフィルタープレスあるいはデカンタで代表される遠心分離機で土砂分離を行い、該土砂分離作業で生じた排土を投入するべく、排土ピットを設けることが多いが、現場の用地内で解膠前の掘削土砂を確保する場合には、かかる排土ピットを形成する位置で行うようにすれば、排土ピットを別途設ける手間を省くことができる。
【０１３９】
次に、このようにして調達された解膠前の掘削土砂を、圧密式ミキサー２の圧搾用シリンダー４１に投入し、次いで、泥水槽３からの循環泥水とともに圧密式ミキサー２の解膠ミキサー４２内で攪拌混合して掘削土砂を解膠し、これを泥水として泥水槽３にいったん貯留し、これを随時、泥水貯留槽４に移して該泥水貯留槽内に貯留する。なお、泥水槽３には随時清水を補充し、該清水が循環泥水の一部として解膠ミキサー４２内に投入されるようにする。
【０１４０】
一方、清水槽８に貯留された清水を混合槽９に入れるとともに、貯留タンク６に貯留された掘削泥水用泥膜形成剤及び掘削泥水用分散剤を所定量混合槽９に添加して適宜希釈混合し、混合液を作製する。また、必要に応じて貯留タンク７内に貯留された炭酸ナトリウム水溶液を添加して混合液を作製する。なお、炭酸ナトリウム水溶液については、添加量が多くなると、逆に塩類凝集を引き起こして分散性が低下するため、あくまで補助的に添加するのが望ましい。
【０１４１】
次に、このように作製された混合液を泥水貯留槽４内に添加する。
【０１４２】
このようにして作製された掘削用泥水を地中連続壁工法の安定液として使用すると、掘削泥水用泥膜形成剤及び掘削泥水用分散剤は、従来のベントナイト等に代わって、例えば粘土を主成分とする１０μｍ以下の細粒分とともに泥水中に分散して低粘性を維持するとともに、掘削泥水用泥膜形成剤による優れた造壁作用により、ろ水量（透水係数）の小さな良質のマッドケーキを切羽や溝壁に形成し、溝壁等を安定させる。
【０１４３】
以上説明したように、本実施形態に係る掘削用泥水の作泥システム及び方法によれば、解膠機である圧密式ミキサー２で掘削土砂を解膠し、次いで、解膠された掘削土砂を清水と混練することで泥水を作製し、しかる後、該泥水に本実施形態で用いる掘削泥水用泥膜形成剤や掘削泥水用分散剤を添加するだけで掘削用泥水を作製することが可能となる。
【０１４４】
すなわち、掘削土砂を解膠しこれを清水とともに混練するようにすれば、細粒分を含んだ泥水を確保することが可能となるとともに、本実施形態で用いる掘削泥水用泥膜形成剤、掘削泥水用分散剤及び清水がいずれも液状であるため、従来のように混練ミキサーやストックヤードを設置するとともに該混練ミキサーを使った手間のかかる溶解作業を行わずとも、これらを混合槽９で単に混合して泥水貯留槽４に添加するだけで掘削用泥水を容易に作製することができる。
【０１４５】
したがって、従来のような作泥プラントを設置する必要がないことはもちろん、工事開始時においても、新規に掘削用泥水を購入したり他の現場から調達することなく、各現場にて掘削用泥水を迅速かつ容易に作製することが可能となる。
【０１４６】
なお、泥水貯留槽４内の泥水中には、細粒分のみならず粗粒分も当然含まれることとなるが、本実施形態で作製された掘削用泥水を用いて地盤掘削を行うにあたっては、地中連続壁工法にしろ、泥水シールド工法にしろ、土砂分離装置で粗粒分が除去されるため、上述した掘削用泥水に粗粒分が含まれていても、何ら問題とはならない。
【０１４７】
また、本実施形態に係る掘削用泥水の作泥システム及び方法によれば、上述した掘削泥水用泥膜形成剤及び掘削泥水用分散剤を併用するようにしたので、掘削泥水用泥膜形成剤の優れた造壁性に掘削泥水用分散剤の優れた耐セメント性とが相まって、地中連続壁工法で使用する場合に特に顕著な作用効果を奏する。
【０１４８】
すなわち、地中連続壁工法においては、掘削用泥水の循環使用に伴ってコンクリートからカルシウムイオンが溶出し、泥水中のカルシウムイオン濃度が上昇して分散性及び造壁性が低下するが、工事初期の段階で添加された掘削泥水用分散剤が工事進行に伴って増大するカルシウムイオンによる分散性低下を抑制する。したがって、本発明で得られた掘削用泥水であれば、これを地中連続壁工法で循環使用しても、造壁性や低粘性は良好に維持される。
【０１４９】
本実施形態では、解膠機として圧密式ミキサー２を用いるようにしたが、これに代えて、鉢形の胴体の中心に配置された円錐形の主軸に偏心的な旋回運動を与え、そのときの圧力によって掘削土砂を粉砕解膠することができるジャイレトリクラッシャーや、その一種であるコーンクラッシャなどを用いることができる。
【０１５０】
また、本実施形態では、解膠機によって掘削土砂を解膠するようにしたが、必ずしも解膠機による必要はなく、図３を参照して第１実施形態で説明したと同様、清水を満たしつつ水平多軸式掘削機５１で地盤を掘削し、その掘削によって解膠された土砂を用いるようにしてもよい。
【０１５１】
なお、水平多軸式掘削機を用いる場合には、掘削されたピット状の凹部５２に解膠された掘削土砂と清水とが該水平多軸式掘削機の回転ドラムの回転動作によって混練されることとなるため、かかる解膠された掘削土砂と清水とが混練されてなる泥水を揚泥し、これをそのまま泥水槽３に貯留することができる。
【０１５２】
なお、泥水槽３にいったん貯留された泥水を随時泥水貯留槽４に移すとともに、混合液を混合槽９で作製しこれを泥水貯留槽４内に添加する手順については、上述の実施形態と同様であることは言うまでもない。この点、第１実施形態でも同様である。
【０１５３】
また、本実施形態では、泥水槽３のほかに該泥水槽内の泥水を移送貯留する泥水貯留槽４を設けるようにしたが、いずれかを省略してもかまわない。なお、泥水貯留槽４を省略した場合には、泥水槽３が本発明でいうところの泥水貯留槽となる。
【０１５４】
また、本実施形態では、掘削泥水用泥膜形成剤及び掘削泥水用分散剤を泥水貯留槽４に添加するようにしたが、これに代えて泥水槽３に添加するようにしてもよく、かかる場合であっても、その下流側に配置された泥水貯留槽４内の泥水に上述した薬剤が添加されることに何ら変わりはない。
【０１５５】
また、本実施形態では、泥水槽３からの循環泥水とともに圧密式ミキサー２の解膠ミキサー４２内で攪拌混合することで掘削土砂を解膠し、これを泥水として泥水槽３に貯留するようにしたが、これに代えて、泥水槽３内の泥水は解膠ミキサー４２に循環させず、清水を解膠ミキサー４２内に投入して泥水を作製し、これを泥水槽３に貯留するようにしてもよい。
【０１５６】
また、本実施形態では特に言及しなかったが、掘削工事がいったん開始した後は、本来掘削すべき箇所から多量の掘削土砂が発生するので、かかる掘削土砂に含まれる細粒分を利用すれば、上述したと同様に掘削用泥水を作製することができる。
【０１５７】
また、本実施形態では、貯留タンク７を設けて該タンク内に炭酸ナトリウム水溶液を貯留するようにしたが、本実施形態で用いる掘削泥水用分散剤によってセメント混入時の分散性の低下を十分抑制することができるのであれば、かかる貯留タンク７を省略してもよい。
【０１５８】
また、本実施形態では、本実施形態で用いる掘削泥水用泥膜形成剤及び掘削泥水用分散剤を貯留タンク６内に貯留するようにしたが、工事開始初期であるために、耐セメント性を重視する必要がないのであれば、掘削泥水用分散剤を省略してもかまわない。
【０１５９】
また、本実施形態では、掘削泥水用泥膜形成剤及び掘削泥水用分散剤を併用することを前提とし、これらを貯留タンク６内に貯留するようにしたが、これらの薬剤はいずれも一定の分散性と造壁性を有しているため、場合によっては、いずれかを単独で使用するようにしてもかまわない。一方、掘削泥水用泥膜形成剤及び掘削泥水用分散剤を併用する場合、これらを混合した状態で貯留タンク６内に貯留してもかまわないが、それぞれ専用のタンク内に貯留するようにしてもかまわない。この場合、貯留タンク６は、計２種類備えることとなる。また、掘削泥水用分散剤としてＳＳ−Ｂ及び炭酸ナトリウムの二種類を使用する場合には、これらを混合した状態で使用してもよいが、それぞれ専用のタンク内に個別に貯留してもかまわない。かかる場合、貯留タンク６は、掘削泥水用分散剤専用、掘削泥水用分散剤（ＳＳ−Ｂ）専用及び掘削泥水用分散剤（炭酸ナトリウム専用）の計３種類となる。
【０１６０】
また、本実施形態では、掘削泥水用泥膜形成剤及び掘削泥水用分散剤を希釈することを前提として、清水槽８や混合槽９を備えるようにしたが、これらを泥水に直接添加しても添加量に関する品質の確保を行うことができるのであれば、清水槽８や混合槽９を省略してもよい。
【０１６１】
また、本実施形態では特に言及しなかったが、混合槽９の下流側に中間貯留槽を設置して該中間貯留槽に混合液をいったん貯留し、しかる後に中間貯留槽内の混合液を泥水貯留槽４に圧送するようにしてもよい。
【０１６２】
また、本実施形態では、地中連続壁工法に適用することを前提としたが、本発明に係る掘削用泥水の作泥システム及び方法は、かかる工法への適用に限定されるものではなく、泥水シールド工法をはじめ、さまざまな泥水工法に適用することが可能である。
【０１６３】
【実施例】
次に、本実施形態で用いる掘削泥水用泥膜形成剤６１を具体的に説明する。なお、特記なき限り、部及び％はそれぞれ質量部及び質量％を示すものとする。
【０１６４】
まず、不飽和カルボン酸及び／又はその塩（ａ）としては、上述した実施形態でも述べたようにアクリル酸ナトリウムとし、これを重合させて単一重合体６１を製造した。
【０１６５】
表４は、重量平均分子量Ｍｗを変化させたときの単一重合体６１の造壁性（ｍｌ）、粘度（濃度；２５質量％）及び泥水と混合したときの泥水粘度（mPa・s）を示したものである。
【０１６６】
ここで、重量平均分子量Ｍｗは、第１実施形態における数平均分子量と同様の測定条件でゲルパーミエーションクロマトグラフにより測定したものである。
【０１６７】
但し、カラムは下記のものを用いる。
カラム ；TSKgel α-3000 + TSKgel α-6000
【０１６８】
なお、標準物質は、ポリオキシエチレングリコール（東ソー株式会社製；TSK STANDARD POLYETHYLENE OXIDE）とし、第１実施形態でも同じものを標準物質とした。
【０１６９】
また、単一重合体６１を添加する前の泥水については、細粒分７５μｍ以下、比重が１．０５となるように濃度調整して作製した。ちなみに、そのときの粘度は１．７ mPa・sであった。泥水粘度はＢ型粘度計にて測定した。また、泥水への添加量はすべて５ｋｇ／ｍ³とした。
【０１７０】
【表４】

【０１７１】
同表中、ブランクと記したものは、泥水のみのケース、実施例１′乃至実施例９′と記したものは、単一重合体６１のうち、造壁性の指標である濾水量が５ｍｌ以下になったケース、比較例１′乃至比較例３′と記したものは、単一重合体６１のうち、濾水量が５ｍｌを上回ったケースである。なお、従来技術と比較すべく、ＣＭＣを用いた場合を比較例４′として併せて示した。
【０１７２】
また、図７は、これらの結果を横軸（対数軸）に重量平均分子量Ｍｗを、縦軸に造壁性（ｍｌ）をとってプロットしたグラフであり、黒丸で表示したものは、比較例１′，２′に相当し、白丸で表示したものは、実施例１′乃至９′に相当する。比較例３′は、造壁性が著しく悪いため、同グラフにはプロットしていない。
【０１７３】
これらの図表でわかるように、造壁性の指標である濾水量が５ｍｌ以下になった実施例１′乃至実施例９′の重量平均分子量Ｍｗは、２０万乃至３００万の範囲に入っており、比較例１′乃至比較例３′は、該濾水量を上回っていることがわかる。また、比較例４′は、濾水量はクリアしていても、泥水粘度が実施例１′乃至実施例９′よりもはるかに高く、掘削用泥水としては粘性が高すぎることがわかる。
【０１７４】
単一重合体６１の製造プロセスを上述した実施例１′の場合について具体的に説明すると、まず、反応容器に水４４０．７部を仕込み、窒素置換した後、８０℃迄昇温し、撹拌下、アクリル酸２３８．５部と、過硫酸ナトリウム２．０％水溶液１００部を同時に３時間かけて滴下し反応した。さらに同温度で２時間熟成した後、イソプロピルアルコールを蒸留により除き、水酸化ナトリウム４８％水溶液２２０．８部で中和した。
【０１７５】
次に、上述した実施例５′に係る単一重合体４１を掘削泥水用分散剤とともに泥水に加えて本実施形態に係る掘削用泥水を作製するとともに、該掘削用泥水にセメントを５％添加し、その耐アルカリ性について実験した。なお、掘削泥水用分散剤としては、上述したＳＳ―Ｂ及び炭酸ナトリウムの二種類をその合計添加量が１kg/m³となるように使用し、それぞれを単独に単一重合体６１と併用した場合と、両方を単一重合体６１と併用した場合について調べた。
【０１７６】
実験結果を表５及び図８に示す。
【０１７７】
【表５】

【０１７８】
これらの図表でわかるように、単一重合体４１に掘削泥水用分散剤を併用した場合（黒丸以外の３ケース）では、掘削泥水用泥膜形成剤を３kg/m³添加すれば所要の造壁性が得られるのに対し、単一重合体４１を単独で使用した場合（黒丸で示したケース）では、掘削泥水用泥膜形成剤を５kg/m³以上添加しなければ所要の造壁性が得られないことがわかる。
【０１７９】
【発明の効果】
以上述べたように、本発明に係る掘削用泥水の作泥システム及び方法によれば、解膠された掘削土砂を清水と混練することで泥水を作製し、しかる後、該泥水に本発明で用いる掘削泥水用泥膜形成剤や掘削泥水用分散剤を添加するだけで掘削用泥水を作製することが可能となる。
【０１８０】
したがって、従来のような作泥プラントを設置する必要がないことはもちろん、工事開始時においても、新規に掘削用泥水を購入したり他の現場から調達することなく、各現場にて掘削用泥水を迅速かつ容易に作製することが可能となる。
【０１８１】
【図面の簡単な説明】
【図１】本実施形態に係る掘削用泥水の作泥システムを示した全体図。
【図２】本実施形態で用いる掘削泥水用泥膜形成剤を示した化学構造式。
【図３】変形例に係る掘削用泥水の作泥システムを示した全体図。
【図４】本実施形態に係る掘削用泥水の作泥システム及び方法に関する実験結果を示したグラフ。
【図５】同じく本実施形態に係る掘削用泥水の作泥システム及び方法に関する実験結果を示したグラフ。
【図６】第２実施形態で用いる掘削泥水用泥膜形成剤を示した化学構造式。
【図７】第２実施形態で用いる掘削泥水用泥膜形成剤における造壁性と重量平均分子量との関係を示したグラフ。
【図８】第２実施形態で用いる掘削泥水用分散剤の耐アルカリ性を示したグラフ。
【符号の説明】
１ 掘削用泥水の作泥システム
２ 圧密式ミキサー（解膠機）
３ 泥水槽
４ 泥水貯留槽
６ 貯留タンク
３１ 掘削泥水用泥膜形成剤
３２ メタクリル酸ナトリウム塩（不飽和カルボン酸塩（ａ））
３３ メトキシポリエチレングリコールメタクリレート（モノエステル（ｂ））
４１ 単一重合体（（共）重合体（ｘ′））
４２ アクリル酸ナトリウム（不飽和カルボン酸塩（ａ））[0001]
BACKGROUND OF THE INVENTION
TECHNICAL FIELD The present invention relates to a mud production system and method for excavation mud used in mud construction methods such as a mud shield method and an underground continuous wall method.
[0002]
[Prior art]
In the muddy water methods such as the muddy water shield method and the underground continuous wall method, so-called drilling muddy water is used, and this muddy water for drilling has a good wall-forming property in order to stabilize the face and groove wall. Therefore, it is desirable that the low viscosity be maintained within a range in which liquid leakage is prevented in terms of slurry transportation and the like. The underground continuous wall construction method is also required to have cement resistance.
[0003]
In order to satisfy such a function, conventionally drilling mud using bentonite, CMC, a dispersant, a polymer agent and the like as a mud-making material has been widely used. Such a mud for excavation has a low viscosity maintained because bentonite and the like are well dispersed in the muddy water, and the dispersed bentonite and the like form a good mud cake on the face and the groove wall. Therefore, it becomes possible to secure the water-stopping property and the stability of the face and the groove wall.
[0004]
[Problems to be solved by the invention]
However, since all the mud-making materials such as bentonite, CMC and polymer agent are powders, a mud-making plant consisting of a stockyard for storing them and a kneading mixer for dissolving them is indispensable. At the same time, when a sufficient space could not be secured on the plant site, the plant configuration became complicated, causing a problem of hindering vehicle traffic on the site.
[0005]
Further, in addition to such problems, the above-mentioned mud-making material is inherently difficult to dissolve in water, so even if a kneading mixer is used, it takes time and labor for the dissolution work. There was also a problem that the production naturally took time.
[0006]
In view of such a problem, the applicant has developed a mud drilling system that does not require a mud plant. There was a problem of being forced to transfer from the site or purchase a new one.
[0007]
The present invention has been made in consideration of the above-described circumstances, and an object thereof is to provide a mud drilling system and method capable of securing the drilling mud at each site even in the initial stage of construction. To do.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, a mud mud production system for excavation according to the present invention includes, as described in claim 1, a mud water storage tank for storing mud water in which peptized excavated sediment and fresh water are kneaded. Added to the muddy water filled in the muddy water storage tank Mud film forming agent for drilling mud And a storage tank in which the mud film forming agent for drilling mud is configured in a liquid state and configured to have a predetermined dispersibility and wall-forming property by being combined with fine particles of the drilling earth and sand, Mud film forming agent for drilling mud, unsaturated carboxylic acid and / or salt thereof (a), unsaturated carboxylic acid (b1) and the following general formula (1)
R (OA) _n OH (1)
R; hydrogen or hydrocarbon group having 1 to 12 carbon atoms
A; an alkylene group having 2 to 4 carbon atoms
n; an integer from 1 to 100
And a copolymer (x) having a monoester (b) of the hydroxyl group-containing compound (b2) represented by By setting the mass% of the monoester (b) constituting the copolymer (x) to 1 to 40% and the number average molecular weight of the copolymer (x) to 5000 to 100,000, bentonite and CMC Was made unnecessary as mud material Is.
[0009]
The mud drilling mud production system according to the present invention includes a mud storage tank for storing mud water obtained by kneading peptized excavated sediment and fresh water, and added to the mud filled in the mud water storage tank. Be done Mud film forming agent for drilling mud And a storage tank in which the mud film forming agent for drilling mud is configured in a liquid state and configured to have a predetermined dispersibility and wall-forming property by being combined with fine particles of the drilling earth and sand, Mud film forming agent for drilling mud, unsaturated carboxylic acid and / or salt thereof (a) Only as a structural unit (Co) polymer (x ′) having a weight average molecular weight Mw of 200,000 to 3,000,000 only By configuring with Bentonite and CMC were made unnecessary as mud materials. Is.
[0010]
The drilling mud production system according to the present invention stores a liquid drilling mud dispersant in the storage tank, and the drilling mud dispersant is a polyacrylic polymer having a weight average molecular weight Mw of 10,000 to 14,000. An acid salt, a polymethacrylate salt or a copolymer thereof, or sodium carbonate.
[0011]
Moreover, the mud production system for excavation mud according to the present invention includes a peptizer for producing the peptized excavated sediment.
[0012]
In addition, the method for producing mud for excavation according to the present invention, as described in claim 5, is a mud that is obtained by kneading peptized excavated soil and fresh water. Mud film forming agent for drilling mud A method for producing excavation mud water by adding a mud film for excavation mud film for drilling mud, which is made liquid by combining the mud film forming agent for excavation mud water with fine particles of excavated sediment. The muddy film forming agent for drilling mud is composed of an unsaturated carboxylic acid and / or a salt thereof (a), an unsaturated carboxylic acid (b1) and the following general formula (1).
R (OA) _n OH (1)
R; hydrogen or hydrocarbon group having 1 to 12 carbon atoms
A; an alkylene group having 2 to 4 carbon atoms
n; an integer from 1 to 100
And a copolymer (x) having a monoester (b) of the hydroxyl group-containing compound (b2) represented by By setting the mass% of the monoester (b) constituting the copolymer (x) to 1 to 40% and the number average molecular weight of the copolymer (x) to 5000 to 100,000, bentonite and CMC Was made unnecessary as mud material Is.
[0013]
Moreover, the mud making method for excavation mud according to the present invention is a mud produced by kneading peptized excavated sediment and fresh water. Mud film forming agent for drilling mud A method for producing excavation mud water by adding a mud film for excavation mud film for drilling mud, which is made liquid by combining the mud film forming agent for excavation mud water with fine particles of excavated sediment. It is configured to have wall properties, and the mud film forming agent for drilling mud is an unsaturated carboxylic acid and / or a salt thereof (a) Only as a structural unit (Co) polymer (x ′) having a weight average molecular weight Mw of 200,000 to 3,000,000 only By configuring with Bentonite and CMC were made unnecessary as mud materials. Is.
[0014]
Further, in the mud production method for excavation mud according to the present invention, a liquid excavation mud dispersant is stored in the storage tank, and the excavation mud dispersant is a polyacrylic polymer having a weight average molecular weight Mw of 10,000 to 14,000. An acid salt, a polymethacrylate salt or a copolymer thereof, or sodium carbonate.
[0015]
In the muddy water excavation method such as the underground continuous wall method and the muddy water shield method, in order to stabilize the groove wall and face, a good quality mud film (mud cake) with low drainage is formed on the groove wall and the muddy water pressure is reduced. It is necessary to effectively act on a wall or the like, and for that purpose, a mud-making material having wall-forming properties such as bentonite, CMC, and a polymer agent has been indispensable conventionally.
[0016]
However, since these mud-making materials are premised on the installation of a mud plant, it is possible for the applicant to create mud for drilling using only excavated soil and water without installing a mud plant. As a result of repeating various experiments, it is possible to ensure the stability of the wall construction at the groove wall and face by using only the excavated soil and water, and the drilling mud dispersant and new excavation. Succeeded in developing a muddy film forming agent.
[0017]
Furthermore, the present applicant has developed a technique for individually securing the drilling mud at each site without procuring from outside even at the beginning of the construction.
[0018]
Specifically, in the mud drilling mud system and method according to claims 1 to 7, first, the excavated sediment generated by ground excavation is peptized, and then the deflated excavated sediment is mixed with fresh water. Then, muddy water is produced, and then the muddy water is stored in a muddy water storage tank.
[0019]
Next, the mud film forming agent for drilling mud stored in the storage tank is added to the mud stored in the mud stored in the mud storage tank to produce the drilling mud.
[0020]
In this way, muddy water is prepared by kneading the peptized excavated sediment with clean water, and then, if the mud film forming agent for drilling mud used in the present invention is added to the muddy water, conventional mud production Of course, it is not necessary to install a plant, and at the start of construction, drilling mud can be quickly and easily created at each site without purchasing new drilling mud or procuring from other sites. Is possible.
[0021]
In addition, the mud film forming agent for drilling mud used in the present invention has a function of ensuring the wall-forming property at the groove wall or face only with the excavated soil and water and ensuring the stability. Therefore, the above-mentioned mud film forming agent for drilling mud can be used without any need for mud-making materials such as bentonite, CMC, and polymer agent, which were indispensable in the past. It goes without saying that the drilling mud can be produced quickly and easily simply by supplementing as necessary.
[0022]
In addition, once the excavation work is started, a large amount of excavated soil is generated from the location that should be excavated. Therefore, if such excavated sediment is used, the excavated mud can be produced in the same manner as described above.
[0023]
Excavation sediment to be peptized, in other words, excavated sediment before peptization should be one that has been brought in from another site, or one excavated by a backhoe or bucket-type kerry excavator on the site Can do.
[0024]
The peptization method may be peptized by any method as long as the excavated sediment is peptized. It is possible to easily obtain the defatted excavated sediment by simply introducing the excavated sediment that has been carried in from the actual site or the sediment excavated in the site of the site.
[0025]
The peptizer can be appropriately selected from various mixers such as a compacting mixer, a pressing mixer, and a paddle mixer.
[0026]
In addition, the muddy water made by kneading the peptized excavated soil and fresh water can be used by excavating the ground with a horizontal multi-axis excavator while filling the fresh water and pumping up the mud from the excavation groove. It is.
[0027]
It should be noted that whatever method is used to produce the drilling mud, the drilling mud naturally contains not only fine particles but also coarse particles. When performing ground excavation using the excavation mud produced in the invention, whether it is the underground continuous wall method or the mud shield method, coarse particles are removed by the sediment separator, so the excavation mud described above Even if coarse particles are contained in this, there is no problem.
[0028]
The mud film forming agent for drilling mud used in the present invention is liquid and has a predetermined dispersibility and wall-forming property by being combined with fine particles of the drilling earth and sand, and unsaturated carboxylic acid and / or Or a salt thereof (a), an unsaturated carboxylic acid (b1) and the following general formula (1)
R (OA) _n OH (1)
R; hydrogen or hydrocarbon group having 1 to 12 carbon atoms
A; an alkylene group having 2 to 4 carbon atoms
n; an integer from 1 to 100
And a copolymer (x) having a monoester (b) of the hydroxyl group-containing compound (b2) represented by By setting the mass% of the monoester (b) constituting the copolymer (x) to 1 to 40% and the number average molecular weight of the copolymer (x) to 5000 to 100,000, bentonite and CMC To make it unnecessary as a mud material Or an unsaturated carboxylic acid and / or a salt thereof (a) Only as a structural unit (Co) polymer (x ′) having a weight average molecular weight Mw of 200,000 to 3,000,000 only By configuring with Bentonite and CMC are made unnecessary as mud materials. .
[0029]
About such a mud film forming agent for drilling mud, since it has a certain dispersibility and wall-forming property, it may be used alone, A liquid dispersant for drilling mud composed of at least one of polyacrylate, polymethacrylate, copolymers thereof or sodium carbonate having a weight average molecular weight Mw of 10,000 to 14,000 is stored in the chemical tank. When the drilling mud dispersant is used in combination with a drilling mud film forming agent In particular, the excellent wall-forming properties of the drilling mud film forming agent combined with the excellent cement resistance of the drilling mud dispersant is particularly prominent when used in the underground continuous wall construction method or on-site concrete pile construction method. There are various effects.
[0030]
That is, in the underground continuous wall construction method, calcium ions are eluted from the concrete with the circulation use of the drilling mud, and the calcium ion concentration in the mud rises. If the dispersant for digging is used in combination, the dispersibility degradation due to calcium ions is suppressed by the dispersant for digging mud. Even when used, the wall-forming property and low viscosity are maintained well.
[0031]
Whether or not a mud film forming agent for drilling mud is used alone or in combination with a dispersant for drilling mud, it is conceivable that sodium carbonate suppresses a decrease in dispersibility due to calcium ions. On the other hand, when the amount of added is increased, salt aggregation is conversely caused and the dispersibility is lowered. Therefore, it is desirable to use sodium carbonate as an auxiliary.
[0032]
In producing the mud film forming agent for drilling mud described above, a known production method, for example, a solution polymerization method may be used. That is, an unsaturated carboxylic acid and / or a salt thereof (a) and a monoester (b) are added as two types of monomers to a predetermined solvent, and then added at 50 to 150 ° C. under normal pressure or The polymerization may be performed under pressure.
[0033]
As the solvent, for example, water, isopropyl alcohol, toluene, ethylene dichloride, methyl ethyl ketone, or a mixture thereof can be used.
[0034]
In the polymerization, 0.1 to 15% by mass of a radical polymerization initiator is used with respect to the total mass of the unsaturated carboxylic acid and / or salt (a) and monoester (b), and a chain transfer agent is used. It is good to use as needed.
[0035]
Here, as the radical polymerization initiator, persulfates such as potassium persulfate, azo compounds such as azobisisobutyronitrile, peroxides such as benzoyl peroxide and dicumyl peroxide can be used. As the chain transfer agent, sulfur-containing compounds such as lauryl mercaptan, thioglycolic acid and mercaptoethanol can be used.
[0036]
In addition, when a part or all of unsaturated carboxylic acid and / or its salt (a) is unsaturated carboxylate, the unsaturated carboxylic acid which is the precursor, its anhydride, or C1-C4 The lower alkyl ester may be neutralized in advance before polymerization, or the copolymer may be neutralized after polymerization. Examples of the neutralizing agent include alkali metal hydroxides such as potassium hydroxide and sodium hydroxide, ammonium hydroxide, ammonia and the like.
[0037]
In addition, the copolymer (x) is not necessarily an unsaturated carboxylic acid and / or a salt thereof (a) using a monoester (b) of an unsaturated carboxylic acid (b1) and a hydroxyl group-containing compound (b2) as a monomer. The precursor of monoester (b), that is, unsaturated carboxylic acid (b1) or its anhydride or lower alkyl ester having 1 to 4 carbon atoms is used. The copolymer may be copolymerized with an unsaturated carboxylic acid and / or a salt thereof (a), and then reacted with a hydroxyl group-containing compound (b2) to form a copolymer (x).
[0038]
The substance constituting the unsaturated carboxylic acid and / or its salt (a) is arbitrary, and examples thereof include acrylic acid, methacrylic acid, itaconic acid, maleic acid and fumaric acid, and alkali metal salts thereof and It can be suitably selected from the group consisting of ammonium salts. The unsaturated carboxylic acid (b1) is also arbitrary, but can be appropriately selected from the group consisting of acrylic acid, methacrylic acid, itaconic acid, maleic acid and fumaric acid.
[0039]
In the general ester (b), R is hydrogen or an alkylene group in the general formula (1). However, in order to ensure good wall-forming properties, it is usually hydrogen or 1 to 12 carbons, more preferably 1 to 6 carbons. It is preferable that it is an alkylene group. R is an alkyl group (such as a methyl group or octyl group), a cycloalkyl group (such as a cyclohexyl group), an aryl group (such as a phenyl group), an alkylaryl group (such as an ethylphenyl group), or an aralkyl group (such as a benzyl group). Either may be sufficient.
[0040]
Further, in the general formula (1), n is preferably an integer having an average of usually 1 to 100 and further an average of 2 to 90 in order to ensure good wall-forming properties.
[0041]
(B2) includes an aliphatic dihydric alcohol having 2 to 4 carbon atoms, an aliphatic alcohol having 1 to 12 carbon atoms represented by ROH, a phenol or an araliphatic alcohol, and an alkylene having 2 to 4 carbon atoms. Those obtained by adding an oxide are preferred.
[0042]
Examples of the aliphatic dihydric alcohol having 2 to 4 carbon atoms include ethylene glycol, propylene glycol, and 1,4-butanediol.
[0043]
As a C1-C12 aliphatic alcohol, natural alcohol or synthetic alcohol (Ziegler alcohol, oxo alcohol, etc.) may be sufficient. Specific examples include linear or branched saturated aliphatic alcohols such as methyl alcohol, butyl alcohol, pentyl alcohol, hexyl alcohol, lauryl alcohol, isobutyl alcohol, tert-butyl alcohol, and 2-ethylhexyl alcohol, cyclohexyl alcohol, and ethylcyclohexyl alcohol. And cycloaliphatic alcohols such as
[0044]
Examples of phenols include phenol and ethylphenol. Examples of the araliphatic alcohol include benzyl alcohol.
[0045]
Examples of the alkylene oxide having 2 to 4 carbon atoms include ethylene oxide (hereinafter abbreviated as EO) alone; EO and other alkylene oxides (propylene oxide (hereinafter abbreviated as PO), 1,2-butylene oxide, tetrahydrofuran, An alkylene oxide substituted product (epichlorohydrin) and the like], and a mixture of two or more thereof. Particularly preferred among those exemplified is the combined use of EO and EO / PO. The addition mode in the case of using other alkylene oxides with EO may be random addition or block addition, and is not particularly limited.
[0046]
The mass ratio of the monoester (b) constituting the copolymer (x) and the number average molecular weight of the copolymer (x) are arbitrary, but the monoester (b) constituting the copolymer (x) ) Is 1 to 40% and the copolymer (x) has a number average molecular weight of 5,000 to 100,000, it is possible to obtain high wall-forming properties and low viscosity.
[0047]
The copolymer (x) can contain other monomer (c) as a constituent unit in addition to (a) and (b). (C) is not particularly limited as long as it can be copolymerized, and examples thereof include the following (c1) to (c5).
[0048]
(C1) Amide group-containing ethylenically unsaturated monomer: (meth) acrylamide, N-methylol (meth) acrylamide, etc.
[0049]
(C2) (Meth) acrylic acid alkyl esters (alkyl group having 1 to 12 carbon atoms): methyl (meth) acrylate, butyl (meth) acrylate, etc.
[0050]
(C3) Ethylenically unsaturated monomer having a hydroxyl group: hydroxyalkyl (1 to 4 carbon atoms) (meth) acrylate [eg, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, etc.]
[0051]
(C4) An ethylenically unsaturated monomer having a polyalkylene glycol chain other than (b): polyethylene glycol (number average molecular weight 120 to 600) mono (meth) acrylate, polypropylene glycol (number average molecular weight 150 to 450) mono ( (Meth) acrylate, methyl alcohol ethylene oxide 1-4 mol adduct (meth) acrylate, etc.
[0052]
(C5) Quaternary ammonium group-containing ethylenically unsaturated monomer: (meth) acryloyloxyethyltrimethylammonium chloride, (meth) acryloyloxyethyldimethylbenzylammonium chloride, etc.
[0053]
Among these (c1) to (c5), preferred are (c2) to (c4).
[0054]
Moreover, the mass% of the other monomer (c) unit which comprises copolymer (X) is 30% or less normally, Preferably it is 20% or less.
[0059]
Similarly to the polymer (x), the production of the (co) polymer (x ′) of the mud film forming agent for drilling mud may be performed by a known production method, for example, a solution polymerization method. That is, an unsaturated carboxylic acid and / or a salt thereof (a) is added as a monomer to a predetermined solvent, and then polymerized at 50 to 150 ° C. under normal pressure or pressure.
[0060]
The type of solvent, single polymerization method, radical polymerization initiator, and neutralization process are the same as those for the mud film forming agent for drilling mud described above, and the description thereof is omitted here.
[0061]
The substance constituting the unsaturated carboxylic acid and / or its salt (a) is arbitrary, and examples thereof include acrylic acid, methacrylic acid, itaconic acid, maleic acid and fumaric acid, and alkali metal salts thereof and It can be suitably selected from the group consisting of ammonium salts. Here, examples of the alkali metal salt include sodium salt and potassium salt.
[0065]
In addition, the mud film forming agent for drilling mud according to claim 2 may be used in combination with the mud film forming agent for drilling mud according to claim 1 at an arbitrary ratio (for example, a mass ratio of 99: 1 to 1:99). Is possible. Similarly, the mud film forming agent for drilling mud according to claim 6 is used in combination with the mud film forming agent for drilling mud according to claim 5 in an arbitrary ratio (for example, the mass ratio is 99: 1 to 1:99). Is possible.
[0066]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of a mud drilling mud production system and method according to the present invention will be described with reference to the accompanying drawings. Note that components that are substantially the same as those of the prior art are assigned the same reference numerals, and descriptions thereof are omitted.
[0067]
(First embodiment)
[0068]
FIG. 1 is an overall view showing a mud production system for excavation according to the present embodiment. As can be seen from the figure, the mud drilling system 1 for excavation according to the present embodiment produces peptized excavated sediment, in other words, for example, lumped excavated sediment that has not yet been peptized. A compacting mixer 2 as a peptizer, a mud tank 3 for storing mud mixed with excavated soil and fresh water peptized by the compacting mixer, and mud water in which the mud in the mud tank is transferred and stored A storage tank 4, a storage tank 6 storing a mud film forming agent for drilling mud and a dispersant for drilling mud added to the mud stored in the mud storage tank 4, and a storage storing an aqueous sodium carbonate solution The tank 7, a fresh water tank 8, and a mixing tank 9 are generally configured.
[0069]
The compacting mixer 2 includes a squeezing cylinder 41 and a peptizer mixer 42 arranged below the squeezing cylinder 41, and accommodates unpeptized excavated sediment introduced from above the squeezing cylinder 41 in the inside of the squeezing cylinder. By pushing down with a piston body (not shown), the excavated earth and sand that has been cut from a mesh strainer provided at the bottom of the squeezing cylinder 41 is pushed out and dropped into the peptizer mixer 42. ing.
[0070]
On the other hand, an underwater sand pump 43 with stirring blades is provided at the bottom of the peptizer mixer 42, and the thread-triggered excavated sediment pushed out from the bottom of the squeezing cylinder 41 is stirred together with the mud water circulated from the mud tank 3. By mixing, the excavated sediment is peptized and sent to the mud tank 3 as mud containing the disaggregated excavated sediment.
[0071]
When uncrushed excavated soil contains a lot of crushed stones and gravel, it is desirable to install a vibrating screen above the squeezing cylinder 41. As such a vibration sieve, for example, a vibration sieve using a grizzly river can be used.
[0072]
In the storage tank 6, the mud film forming agent for drilling mud and the dispersant for drilling mud used in the present embodiment are stored, and the dispersant for drilling mud is driven by driving the pump 15 connected to the tank. And the mud film forming agent for drilling mud can be pumped to the mixing tank 9 through the pipe 16.
[0073]
Further, as described above, the sodium carbonate (sodium carbonate) aqueous solution is stored in the storage tank 7, and the sodium carbonate aqueous solution is mixed via the pipe 18 by driving the pump 17 connected to the tank. It can be pumped to the tank 9.
[0074]
Fresh water is stored in the fresh water tank 8, and the fresh water can be pumped to the mixing tank 9 through the pipe 20 by driving a pump 19 connected to the tank.
[0075]
The mixing tank 9 mixes the mud film forming agent for drilling mud, the dispersant for drilling mud, and fresh water to prepare a mixed liquid to be added to the mud, and drives a pump 21 connected to the mixing tank. Thus, the liquid mixture can be pumped into the muddy water storage tank 4 through the pipe 22. The mixing tank 9 may be provided with a stirring mechanism (not shown) as necessary.
[0076]
The mud film forming agent for drilling mud used in the present embodiment includes an unsaturated carboxylic acid and / or a salt thereof (a), an unsaturated carboxylic acid (b1), and the following general formula (1).
R (OA) _n OH (1)
R; hydrogen or hydrocarbon group having 1 to 12 carbon atoms
A; an alkylene group having 2 to 4 carbon atoms
n; an integer from 1 to 100
And a copolymer (x) from a monoester (b) of the hydroxyl group-containing compound (b2).
[0077]
The mass ratio of the monoester (b) to the copolymer (x) is preferably 1% to 40%. This is because when the mass% of the monoester (b) with respect to the copolymer (x) is less than 1%, the wall-forming property is lowered regardless of the amount of the mud film forming agent for drilling mud, and it exceeds 40%. This is because, when the amount of the mud film forming agent for drilling mud is low, agglomeration may occur and the wall-forming property may deteriorate.
[0078]
Further, the number average molecular weight of the copolymer (x) is preferably 5,000 to 100,000. If the number average molecular weight is less than 5000, the wall-forming property is lowered regardless of the amount of the mud film forming agent for drilling mud, and if it exceeds 100,000, the amount of the mud film forming agent for drilling mud is low. This is because agglomeration may occur and the wall-forming property may deteriorate.
[0079]
In addition, about a number average molecular weight, it shall measure with a gel permeation chromatograph.
[0080]
FIG. 2 shows an example of a mud film forming agent 31 for drilling mud, in which unsaturated carboxylic acid and / or its salt (a) is composed of sodium methacrylate 32 and monoester (b) is composed of methoxypolyethylene glycol methacrylate 33. Is a chemical structural formula (chemical formula) shown as
[0081]
On the other hand, the drilling mud dispersant used in the present embodiment is a polyacrylate, polymethacrylate or a copolymer thereof having a weight average molecular weight Mw of 10,000 to 14,000. Etc. are arbitrary, for example, it can be comprised from the sodium salt of polyacrylic acid whose weight average molecular weight Mw is 10,000-14000. Specifically, a dispersant for a polycarboxylic acid-based stabilizer (hereinafter simply referred to as SS-B) commercially available under the trade name SUPER SLRRY B (manufactured by Sanyo Chemical Industries, Ltd.) can be used.
[0082]
In order to produce excavation mud using the excavation mud mud production system 1 according to the present embodiment, first, excavated soil before peptization is carried in from another site or backhoe in the site of the site. It is procured by excavation using a bucket-type kerry excavator.
[0083]
In the continuous underground wall method and the muddy water shield method, the soil is separated by a centrifuge such as a sediment separator, filter press or decanter, and the soil generated in the sediment separation operation is put into the soil. In many cases, pits are provided. However, when excavating soil before peptization is secured in the site, it is possible to save the trouble of separately installing the earth pits if it is performed at the position where such earth pits are formed. be able to.
[0084]
Next, the pre-peptized excavated soil that has been procured in this way is put into the squeezing cylinder 41 of the compacting mixer 2, and then the peptizer mixer 42 of the compacting mixer 2 together with the circulating mud from the mud tank 3. Then, the excavated sediment is peptized and stored in the mud tank 3 as muddy water, which is transferred to the mud tank 4 and stored in the mud tank. The mud tank 3 is replenished with fresh water as needed, and the fresh water is introduced into the peptizer mixer 42 as a part of the circulating mud.
[0085]
On the other hand, the fresh water stored in the fresh water tank 8 is put into the mixing tank 9, and the mud film forming agent for drilling mud and the dispersant for drilling mud stored in the storage tank 6 are added to the mixing tank 9 and diluted appropriately. Mix to make a mixture. Moreover, the sodium carbonate aqueous solution stored in the storage tank 7 is added as needed, and a liquid mixture is produced. In addition, about sodium carbonate aqueous solution, when the addition amount increases, on the contrary, salt aggregation will be caused and a dispersibility will fall, Therefore It is desirable to add to the last to the last.
[0086]
Next, the mixed solution thus prepared is added to the muddy water storage tank 4.
[0087]
When the drilling mud thus prepared is used as a stable liquid in the underground continuous wall method, the mud film forming agent for drilling mud and the dispersant for drilling mud are mainly made of clay, for example, instead of conventional bentonite. A good quality mud cake with a small drainage (permeability coefficient) due to the excellent wall-forming action of the mud film forming agent for drilling mud, while maintaining a low viscosity by dispersing in the mud with a fine particle of 10 μm or less as a component. Is formed on the face and groove wall to stabilize the groove wall and the like.
[0088]
As described above, according to the mud production system and method for excavation according to the present embodiment, the excavated sediment is peptized by the compacting mixer 2 which is a peptizer, and then the deflated excavated sediment is removed. It is possible to prepare muddy water by kneading with fresh water, and then to create muddy water for drilling by simply adding the muddy film forming agent for drilling mud and the dispersant for drilling mud used in this embodiment to the muddy water. Become.
[0089]
That is, if the drilling soil is peptized and kneaded with fresh water, it becomes possible to secure mud containing fine particles, and the mud film forming agent for drilling mud used in this embodiment, drilling Since both the muddy water dispersant and the fresh water are in a liquid state, a kneading mixer and a stock yard are installed as in the prior art, and these are simply mixed in the mixing tank 9 without performing a troublesome melting operation using the kneading mixer. By simply mixing and adding to the muddy water storage tank 4, the muddy water for excavation can be easily produced.
[0090]
Therefore, it is not necessary to install a conventional mud production plant, and even at the start of construction, there is no need to purchase new drilling mud or procure from other sites. Can be produced quickly and easily.
[0091]
The mud water in the mud water storage tank 4 naturally includes not only fine particles but also coarse particles, but when performing ground excavation using the excavation mud produced in the present embodiment. Whether the underground continuous wall construction method or the muddy water shield construction method is used, since the coarse particles are removed by the earth and sand separator, there is no problem even if the above-described excavation mud contains the coarse particles.
[0092]
Further, according to the mud mud production system and method for excavation according to the present embodiment, the mud film forming agent for drilling mud and the dispersant for drilling mud are used together. Combined with the excellent wall-forming properties of the drilling mud and the excellent cement resistance of the dispersant for drilling mud, it has a particularly remarkable effect when used in the underground continuous wall construction method.
[0093]
In other words, in the underground continuous wall method, calcium ions are eluted from the concrete with the use of mud for excavation, and the calcium ion concentration in the mud increases and the dispersibility and wall-forming properties decrease. The dispersant for drilling mud added at this stage suppresses the decrease in dispersibility due to calcium ions, which increases with the progress of construction. Therefore, if it is the mud for excavation obtained by this invention, even if this is circulated and used by the underground continuous wall construction method, wall-forming property and low viscosity are maintained favorable.
[0094]
In the present embodiment, the compacting mixer 2 is used as the peptizer, but instead, an eccentric swiveling motion is given to the conical main shaft disposed at the center of the bowl-shaped body, A gyratory crusher that can pulverize and plow the excavated sediment by pressure, or a cone crusher that is a kind thereof can be used.
[0095]
Further, in this embodiment, the excavated sediment is peptized by the peptizer, but it is not always necessary to use the peptizer. For example, as shown in FIG. 3, the horizontal multi-axis excavator 51 is filled with fresh water. Then, the ground may be excavated and the soil peptized by the excavation may be used.
[0096]
When a horizontal multi-axis excavator is used, the excavated soil and fresh water peptized in the excavated pit-shaped recess 52 are kneaded by the rotating operation of the rotary drum of the horizontal multi-axis excavator. Therefore, the muddy water obtained by kneading the peptized excavated earth and fresh water can be pumped up and stored in the mud tank 3 as it is.
[0097]
In the present embodiment, in addition to the muddy water tank 3, the muddy water storage tank 4 for transferring and storing the muddy water in the muddy water tank is provided, but either of them may be omitted. In addition, when the muddy water storage tank 4 is omitted, the muddy water tank 3 is a muddy water storage tank as referred to in the present invention.
[0098]
Moreover, in this embodiment, although the mud film forming agent for drilling mud and the dispersing agent for drilling mud were added to the mud storage tank 4, it may replace with this and may be added to the mud tank 3. Even if it is a case, it does not change at all that the chemical | medical agent mentioned above is added to the muddy water in the muddy water storage tank 4 arrange | positioned in the downstream.
[0099]
Further, in the present embodiment, the excavated sediment is peptized by stirring and mixing in the peptizer mixer 42 of the compacting mixer 2 together with the circulating mud from the mud tank 3 so as to be stored in the mud tank 3 as muddy water. However, instead of this, the muddy water in the muddy water tank 3 is not circulated to the peptizer mixer 42, but fresh water is introduced into the peptizer mixer 42 to produce muddy water, which is stored in the muddy water tank 3. May be.
[0100]
Although not particularly mentioned in the present embodiment, after excavation work is started once, a large amount of excavated earth and sand is generated from the place to be excavated, so if fine particles contained in such excavated earth and sand are used. The mud for excavation can be produced in the same manner as described above.
[0101]
Further, in this embodiment, the storage tank 7 is provided to store the sodium carbonate aqueous solution in the tank, but the dispersion of the cement mud is sufficiently suppressed by the drilling mud dispersant used in this embodiment. If it is possible, the storage tank 7 may be omitted.
[0102]
Further, in this embodiment, the mud film forming agent for drilling mud and the dispersant for drilling mud used in the present embodiment are stored in the storage tank 6. If it is not necessary to place importance, the drilling mud dispersant may be omitted.
[0103]
In the present embodiment, the mud film forming agent for drilling mud and the dispersant for drilling mud are used in combination, and these are stored in the storage tank 6. Since it has dispersibility and wall-forming property, depending on the case, either one may be used alone. On the other hand, when the mud film forming agent for drilling mud and the dispersant for drilling mud are used in combination, they may be stored in the storage tank 6 in a mixed state. It doesn't matter. In this case, a total of two storage tanks 6 are provided.
[0104]
Moreover, in this embodiment, it was provided with the fresh water tank 8 and the mixing tank 9 on the assumption that the mud film forming agent for drilling mud and the dispersant for drilling mud were diluted, but these were directly added to the mud. If the quality regarding addition amount can also be ensured, you may abbreviate | omit the fresh water tank 8 and the mixing tank 9. FIG.
[0105]
Although not particularly mentioned in the present embodiment, an intermediate storage tank is installed on the downstream side of the mixing tank 9, and the mixed liquid is temporarily stored in the intermediate storage tank. Thereafter, the mixed liquid in the intermediate storage tank is muddy water. You may make it pressure-feed to the storage tank 4. FIG.
[0106]
Further, in this embodiment, it is assumed that it is applied to the underground continuous wall construction method, but the mud drilling mud system and method according to the present invention is not limited to application to such construction method, It can be applied to various muddy water methods including the muddy water shield method.
[0107]
Moreover, in this embodiment, since the remarkable effect was confirmed by experiment, the mass% of monoester (b) which comprises copolymer (x) is 1 to 40%, and the number average of copolymer (x) Although the molecular weight is set to 5000 to 100,000, the mud film forming agent for drilling mud used in the present invention is not limited to such a range, and a certain effect can be obtained even outside the range described in the embodiment. Is possible.
[0108]
Moreover, in this embodiment, although SS-B was mentioned as an example as a dispersing agent for drilling mud, it may replace with this and may use sodium carbonate.
[0109]
【Example】
Next, the mud film forming agent for drilling mud used in the present embodiment will be specifically described. Unless otherwise specified, parts and% indicate parts by mass and% by mass, respectively.
[0110]
First, as the unsaturated carboxylic acid and / or its salt (a), two kinds of sodium methacrylate (hereinafter referred to as a-1) and sodium acrylate (hereinafter referred to as a-2) were used in the experiment. Moreover, as unsaturated carboxylic acid ester (b), 10 types of unsaturated carboxylic acid ester are used, and unsaturated which comprises these 10 types of unsaturated carboxylic acid ester (henceforth, b-1-b-10). Table 1 shows the composition of the carboxylic acid (b1) and the hydroxyl group-containing compound (b2). In the table, EO and PO indicate ethylene oxide and propylene oxide, respectively.
[0111]
[Table 1]

[0112]
Next, a copolymer (x) by combining the above-mentioned sodium methacrylate (a-1) and sodium acrylate (a-2) with 10 types of unsaturated carboxylic acid esters (b-1 to b-10). Table 2 shows the composition ratio, the monoester content ratio (%), and the number average molecular weight (hereinafter referred to as Examples 1 to 16). In addition, the measurement conditions of a number average molecular weight are shown below.
[0113]

[0114]
[Table 2]

[0115]
In producing the mud film forming agent for drilling mud of Examples 1 to 16 described above, first, 363 parts of water and 196 parts of isopropyl alcohol were charged into a reaction vessel, and after nitrogen substitution, the temperature was raised to 80 ° C. Under stirring, 151 parts (1.757 moles) of methacrylic acid, 48 parts (0.036 moles) of methoxypolyethylene glycol (28 moles of added ethylene oxide) and 39.8% aqueous solution of sodium persulfate 39.8 are mixed. Parts (0.008 mol of sodium persulfate) were simultaneously added dropwise over 3 hours to react. Further, after aging at the same temperature for 2 hours, isopropyl alcohol was removed by distillation, neutralized with 146 parts of a 48% aqueous solution of sodium hydroxide (1.757 mol of sodium hydroxide), and then an amount of water to give a solid content of 30%. Was added to obtain a copolymer having a number average molecular weight of 42800 (Example 1). In addition, Examples 2 to 16 were obtained in the same manner as in Example 1 except that the monomer composition was changed so that the structural units shown in Table 2 were obtained.
[0116]
The mud film forming agent for drilling mud of Examples 1 to 16 produced in this manner was added to the mud, and the wall-forming property and mud viscosity were examined (Table 3).
[0117]
Here, the mud before adding the mud film forming agent for drilling mud was prepared by adjusting the concentration so that the fine particle content was 75 μm or less and the specific gravity was 1.05. Incidentally, the viscosity at that time was 11.1 mPa · s. The muddy water viscosity was measured with a B-type viscometer.
[0118]
Moreover, the wall-forming property in the table is slightly different from the index in the API standard, and the amount of drainage when the lower side of the filter paper is in a reduced pressure state in order to accelerate the drainage process and shorten the experiment time. It is measured, and 5 ml or less is regarded as a good wall-forming property. For comparison with the prior art, the case of using CMC is also shown as Comparative Example 1.
[0119]
[Table 3]

[0120]
As can be seen from the table, Examples 1-6, 11-16, regardless of the addition amount, the wall-forming properties are all 5 ml or less, and the muddy water viscosity is also kept low, In other words, while good dispersibility is maintained, in Examples 7 to 10, it can be seen that the wall-forming property is lowered when the addition amount is small.
[0121]
Incidentally, in Comparative Example 1 using CMC, although the wall-forming property can be ensured, the results confirm the problem that the viscosity is increased.
[0122]
Next, the mud film forming agent for drilling mud according to Example 11 described above was added to the mud together with the dispersant for drilling mud to produce the mud for drilling according to this embodiment, and the cement resistance was tested. In addition, as the dispersant for drilling mud, the two types of SS-B and sodium carbonate described above are used, each of which is used in combination with the mud film forming agent for drilling mud, and both are formed as a mud film for drilling mud. It investigated about the case where it used together with an agent.
[0123]
The experimental results are shown in FIGS.
[0124]
First, FIG. 4 shows an experimental result when no cement is added to the above-described excavation mud. As shown in the figure, when the amount of mud film forming agent for drilling mud is about 0.25% or more, the case where the mud film forming agent for drilling mud is used alone (indicated by the black circle) and the drilling mud It can be seen that there is almost no difference in the wall-forming property between the case (3 cases other than the black circle) where the drilling mud dispersant is used in combination with the mud film forming agent.
[0125]
Next, the experimental results when 1% and 5% of cement are added to the excavation mud are shown in FIGS. 5 (a) and 5 (b). As shown in these figures, when the drilling mud mud film forming agent is used in combination with the drilling mud water dispersing agent (three cases other than the black circle), the drilling mud mud film forming agent is 0.1 to 0.2%. If it is added, the required wall-forming property can be obtained, but when the mud film forming agent for drilling mud is used alone (indicated by the black circle), the mud film forming agent for drilling mud is 1% cement. It can be seen that the required wall-forming property cannot be obtained unless 0.5% is added in the case of less than 0.3% and cement is 5%.
[0126]
(Second Embodiment)
[0127]
Next, a mud production system and method for excavation mud according to the second embodiment will be described. Note that components that are substantially the same as those of the first embodiment are denoted by the same reference numerals, and description thereof is omitted.
[0128]
That is, the excavation mud mud mud production system according to the second embodiment is also a compacting type as a peptizer for producing the crushed excavation sediment similarly to the excavation mud mud mud production system 1 described in the first embodiment. A mud tank 3 for storing mud mixed with the mixer 2, the excavated sediment and fresh water kneaded by the compacting mixer, the mud water tank 4 for storing and transferring mud in the mud tank, and the mud water A storage tank 6 storing a mud film forming agent for drilling mud and a dispersant for drilling mud added to the mud stored in the storage tank 4, a storage tank 7 storing an aqueous sodium carbonate solution, and a fresh water tank 8 And the mixing tank 9, except that the chemical composition of the mud film forming agent for drilling mud and the dispersant for drilling mud differ from each other, and the mud producing system and configuration for drilling mud according to the first embodiment Are exactly the same and therefore no more The detailed description is omitted here.
[0129]
The mud film forming agent for drilling mud used in the present embodiment comprises a single polymer as a (co) polymer (x ′) having an unsaturated carboxylic acid and / or a salt thereof (a) as a main structural unit, The weight average molecular weight Mw of the single polymer is 200,000 to 3,000,000.
[0130]
Here, the weight average molecular weight Mw of the single polymer was set to 200,000 to 3,000,000. When the weight average molecular weight Mw was less than 200,000, the amount of filtered water, which is an index of wall-forming property, slightly exceeded 5 ml. This is because the amount of filtered water greatly exceeds 5 ml.
[0131]
The amount of filtered water is slightly different from the index in the API standard, and is measured with the lower side of the filter paper under reduced pressure in order to accelerate the filtering process and shorten the experiment time. It is considered to be a good wall-forming property.
[0132]
FIG. 6 is a chemical structural formula (chemical formula) showing an example of a mud film forming agent for drilling mud according to the present embodiment. The unsaturated carboxylic acid and / or its salt (a) is composed of sodium acrylate 62. A drilling mud film forming agent 61 is shown.
[0133]
The lower limit value and upper limit value of the weight average molecular weight Mw are plotted as the results obtained in the experiments described later, and then a curve that approximates these results is created, and the intersection of the curve and the line with a drainage amount of 5 ml The ranges are 200,000 and 3 million, respectively, but the range of the weight average molecular weight Mw is preferably 500,000 to 2.5 million, taking into account the empirical safety factor in consideration of experimental errors and the like.
[0134]
On the other hand, the mud film forming agent 61 for drilling mud is preferably used with a concentration of 20 to 30% by weight added to the mud, but in such a concentration range, when the weight average molecular weight Mw exceeds 1 million, When it is added to muddy water, it is not necessarily excellent in workability.
[0135]
Therefore, it is desirable that the weight average molecular weight Mw of the mud film forming agent 61 for drilling mud is set to 500,000 to 1,000,000 from the viewpoint of such an addition workability. Furthermore, it is optimal to set the weight average molecular weight Mw of the mud film forming agent 61 for drilling mud to be 600,000 to 800,000 in order to clear the upper limit of the drainage amount with a margin and to reliably increase the work of adding to the mud.
[0136]
Next, the drilling mud dispersant used in the present embodiment is a polyacrylate, polymethacrylate, or a copolymer thereof, and its weight average molecular weight Mw is 10,000 to 14,000. The composition is arbitrary, and for example, it can be composed of a sodium salt of polyacrylic acid having a weight average molecular weight Mw of 10,000 to 14,000. Specifically, a dispersant for a polycarboxylic acid-based stabilizer (hereinafter simply referred to as SS-B) commercially available under the trade name SUPER SLRRY B (manufactured by Sanyo Chemical Industries, Ltd.) can be used. Further, sodium carbonate may be used instead of or in addition to SS-B.
[0137]
In order to produce the drilling mud using the drilling mud production system according to the present embodiment, first, the excavated soil before peptization is carried in from other sites or backhoes in the site of the site. Procured by excavating with a bucket-type kerry excavator.
[0138]
In the continuous underground wall method and the muddy water shield method, the soil is separated by a centrifuge such as a sediment separator, filter press or decanter, and the soil generated in the sediment separation operation is put into the soil. In many cases, pits are provided. However, when excavating soil before peptization is secured in the site, it is possible to save the trouble of separately installing the earth pits if it is performed at the position where such earth pits are formed. be able to.
[0139]
Next, the pre-peptized excavated soil that has been procured in this way is put into the squeezing cylinder 41 of the compacting mixer 2, and then the peptizer mixer 42 of the compacting mixer 2 together with the circulating mud from the mud tank 3. Then, the excavated sediment is peptized and stored in the mud tank 3 as muddy water, which is transferred to the mud tank 4 and stored in the mud tank. The mud tank 3 is replenished with fresh water as needed, and the fresh water is introduced into the peptizer mixer 42 as a part of the circulating mud.
[0140]
On the other hand, the fresh water stored in the fresh water tank 8 is put into the mixing tank 9, and the mud film forming agent for drilling mud and the dispersant for drilling mud stored in the storage tank 6 are added to the mixing tank 9 and diluted appropriately. Mix to make a mixture. Moreover, the sodium carbonate aqueous solution stored in the storage tank 7 is added as needed, and a liquid mixture is produced. In addition, about sodium carbonate aqueous solution, when the addition amount increases, on the contrary, salt aggregation will be caused and a dispersibility will fall, Therefore It is desirable to add to the last to the last.
[0141]
Next, the mixed solution thus prepared is added to the muddy water storage tank 4.
[0142]
When the drilling mud thus prepared is used as a stable liquid in the underground continuous wall method, the mud film forming agent for drilling mud and the dispersant for drilling mud are mainly made of clay, for example, instead of conventional bentonite. A good quality mud cake with a small drainage (permeability coefficient) due to the excellent wall-forming action of the mud film forming agent for drilling mud, while maintaining a low viscosity by dispersing in the mud with a fine particle of 10 μm or less as a component. Is formed on the face and groove wall to stabilize the groove wall and the like.
[0143]
As described above, according to the mud production system and method for excavation according to the present embodiment, the excavated sediment is peptized by the compacting mixer 2 which is a peptizer, and then the deflated excavated sediment is removed. It is possible to prepare muddy water by kneading with fresh water, and then to create muddy water for drilling by simply adding the muddy film forming agent for drilling mud and the dispersant for drilling mud used in this embodiment to the muddy water. Become.
[0144]
That is, if the drilling soil is peptized and kneaded with fresh water, it becomes possible to secure mud containing fine particles, and the mud film forming agent for drilling mud used in this embodiment, drilling Since both the muddy water dispersant and the fresh water are in a liquid state, a kneading mixer and a stock yard are installed as in the prior art, and these are simply mixed in the mixing tank 9 without performing a troublesome melting operation using the kneading mixer. By simply mixing and adding to the muddy water storage tank 4, the muddy water for excavation can be easily produced.
[0145]
Therefore, it is not necessary to install a conventional mud production plant, and even at the start of construction, there is no need to purchase new drilling mud or procure from other sites. Can be produced quickly and easily.
[0146]
The mud water in the mud water storage tank 4 naturally includes not only fine particles but also coarse particles, but when performing ground excavation using the excavation mud produced in the present embodiment. Whether the underground continuous wall construction method or the muddy water shield construction method is used, since the coarse particles are removed by the earth and sand separator, there is no problem even if the above-described excavation mud contains the coarse particles.
[0147]
Further, according to the mud mud production system and method for excavation according to the present embodiment, the mud film forming agent for drilling mud and the dispersant for drilling mud are used together. Combined with the excellent wall-forming properties of the drilling mud and the excellent cement resistance of the dispersant for drilling mud, it has a particularly remarkable effect when used in the underground continuous wall construction method.
[0148]
In other words, in the underground continuous wall method, calcium ions are eluted from the concrete with the use of mud for excavation, and the calcium ion concentration in the mud increases and the dispersibility and wall-forming properties decrease. The dispersant for drilling mud added at this stage suppresses the decrease in dispersibility due to calcium ions, which increases with the progress of construction. Therefore, if it is the mud for excavation obtained by this invention, even if this is circulated and used by the underground continuous wall construction method, wall-forming property and low viscosity are maintained favorable.
[0149]
In the present embodiment, the compacting mixer 2 is used as the peptizer, but instead, an eccentric swiveling motion is given to the conical main shaft disposed at the center of the bowl-shaped body, A gyratory crusher that can pulverize and plow the excavated sediment by pressure, or a cone crusher that is a kind thereof can be used.
[0150]
Further, in this embodiment, the excavated sediment is peptized by the peptizer, but it is not always necessary to use the peptizer, and as described in the first embodiment with reference to FIG. Alternatively, the ground may be excavated by the horizontal multi-axis excavator 51, and the soil that has been peptized by the excavation may be used.
[0151]
When a horizontal multi-axis excavator is used, the excavated soil and fresh water peptized in the excavated pit-shaped recess 52 are kneaded by the rotating operation of the rotary drum of the horizontal multi-axis excavator. Therefore, the muddy water obtained by kneading the peptized excavated earth and fresh water can be pumped up and stored in the mud tank 3 as it is.
[0152]
In addition, about the procedure which transfers the muddy water once stored in the muddy water tank 3 to the muddy water storage tank 4 at any time, produces a liquid mixture in the mixing tank 9, and adds this to the muddy water storage tank 4, it is the same as that of the above-mentioned embodiment. Needless to say. This also applies to the first embodiment.
[0153]
In the present embodiment, in addition to the muddy water tank 3, the muddy water storage tank 4 for transferring and storing the muddy water in the muddy water tank is provided, but either of them may be omitted. In addition, when the muddy water storage tank 4 is omitted, the muddy water tank 3 is a muddy water storage tank as referred to in the present invention.
[0154]
Moreover, in this embodiment, although the mud film forming agent for drilling mud and the dispersing agent for drilling mud were added to the mud storage tank 4, it may replace with this and may be added to the mud tank 3. Even if it is a case, it does not change at all that the chemical | medical agent mentioned above is added to the muddy water in the muddy water storage tank 4 arrange | positioned in the downstream.
[0155]
Further, in the present embodiment, the excavated sediment is peptized by stirring and mixing in the peptizer mixer 42 of the compacting mixer 2 together with the circulating mud from the mud tank 3 so as to be stored in the mud tank 3 as muddy water. However, instead of this, the muddy water in the muddy water tank 3 is not circulated to the peptizer mixer 42, but fresh water is introduced into the peptizer mixer 42 to produce muddy water, which is stored in the muddy water tank 3. May be.
[0156]
Although not particularly mentioned in the present embodiment, after excavation work is started once, a large amount of excavated earth and sand is generated from the place to be excavated, so if fine particles contained in such excavated earth and sand are used. The mud for excavation can be produced in the same manner as described above.
[0157]
Further, in this embodiment, the storage tank 7 is provided to store the sodium carbonate aqueous solution in the tank, but the dispersion of the cement mud is sufficiently suppressed by the drilling mud dispersant used in this embodiment. If it is possible, the storage tank 7 may be omitted.
[0158]
Further, in this embodiment, the mud film forming agent for drilling mud and the dispersant for drilling mud used in the present embodiment are stored in the storage tank 6. If it is not necessary to place importance, the drilling mud dispersant may be omitted.
[0159]
In the present embodiment, the mud film forming agent for drilling mud and the dispersant for drilling mud are used in combination, and these are stored in the storage tank 6. Since it has dispersibility and wall-forming property, depending on the case, either one may be used alone. On the other hand, when the mud film forming agent for drilling mud and the dispersant for drilling mud are used in combination, they may be stored in the storage tank 6 in a mixed state. It doesn't matter. In this case, the storage tank 6 is provided with two types in total. When using two types of dispersant for drilling mud, SS-B and sodium carbonate, they may be used in a mixed state, but they may be stored separately in dedicated tanks. Absent. In such a case, the storage tank 6 has three types in total: a drilling mud dispersant, a drilling mud dispersant (SS-B), and a drilling mud dispersant (sodium carbonate only).
[0160]
Moreover, in this embodiment, it was provided with the fresh water tank 8 and the mixing tank 9 on the assumption that the mud film forming agent for drilling mud and the dispersant for drilling mud were diluted, but these were directly added to the mud. If the quality regarding addition amount can also be ensured, you may abbreviate | omit the fresh water tank 8 and the mixing tank 9. FIG.
[0161]
Although not particularly mentioned in the present embodiment, an intermediate storage tank is installed on the downstream side of the mixing tank 9 to temporarily store the mixed liquid in the intermediate storage tank, and then the mixed liquid in the intermediate storage tank is muddy water. You may make it pressure-feed to the storage tank 4. FIG.
[0162]
Further, in this embodiment, it is assumed that it is applied to the underground continuous wall construction method, but the mud drilling mud system and method according to the present invention is not limited to application to such construction method, It can be applied to various muddy water methods including the muddy water shield method.
[0163]
【Example】
Next, the mud film forming agent 61 for drilling mud used in the present embodiment will be specifically described. Unless otherwise specified, parts and% indicate parts by mass and% by mass, respectively.
[0164]
First, as the unsaturated carboxylic acid and / or its salt (a), sodium acrylate was used as described in the above embodiment, and this was polymerized to produce a single polymer 61.
[0165]
Table 4 shows the wall-forming property (ml), viscosity (concentration: 25% by mass) of the single polymer 61 when the weight average molecular weight Mw is changed, and muddy water viscosity (mPa · s) when mixed with muddy water. It is a thing.
[0166]
Here, the weight average molecular weight Mw is measured by gel permeation chromatograph under the same measurement conditions as the number average molecular weight in the first embodiment.
[0167]
However, the following columns are used.
Column: TSKgel α-3000 + TSKgel α-6000
[0168]
The standard material was polyoxyethylene glycol (manufactured by Tosoh Corporation; TSK STANDARD POLYETHYLENE OXIDE), and the same material was used as the standard material in the first embodiment.
[0169]
Further, the muddy water before the addition of the single polymer 61 was prepared by adjusting the concentration so that the fine particle content was 75 μm or less and the specific gravity was 1.05. Incidentally, the viscosity at that time was 1.7 mPa · s. The muddy water viscosity was measured with a B-type viscometer. The amount added to the muddy water is 5 kg / m. ^Three It was.
[0170]
[Table 4]

[0171]
In the same table, a blank indicates a case of only muddy water, and those described as Examples 1 ′ to 9 ′ indicate that the amount of filtrate that is an index of wall-forming property is 5 ml or less in the single polymer 61. The cases described as Comparative Example 1 ′ to Comparative Example 3 ′ are cases in which the amount of filtered water of the single polymer 61 exceeds 5 ml. For comparison with the prior art, the case of using CMC is also shown as Comparative Example 4 ′.
[0172]
FIG. 7 is a graph in which these results are plotted with the weight average molecular weight Mw on the horizontal axis (logarithmic axis) and the wall-forming property (ml) on the vertical axis. 1 'and 2', and those indicated by white circles correspond to Examples 1 'to 9'. Comparative Example 3 ′ is not plotted in the graph because the wall-forming property is extremely poor.
[0173]
As can be seen from these charts, the weight average molecular weights Mw of Examples 1 ′ to 9 ′ in which the amount of filtered water, which is an index of wall-forming property, is 5 ml or less are in the range of 200,000 to 3 million. It can be seen that Comparative Examples 1 'to 3' exceed the drainage amount. Further, it can be seen that Comparative Example 4 ′ has a much higher mud viscosity than Examples 1 ′ to 9 ′ even when the drainage amount is clear, and is too viscous as a mud for excavation.
[0174]
The production process of the single polymer 61 will be specifically described in the case of Example 1 ′ described above. First, 440.7 parts of water was charged into a reaction vessel, and after the atmosphere was replaced with nitrogen, the temperature was raised to 80 ° C. and stirred. Then, 238.5 parts of acrylic acid and 100 parts of a 2.0% aqueous solution of sodium persulfate were dropped simultaneously over 3 hours to react. Further, after aging at the same temperature for 2 hours, isopropyl alcohol was removed by distillation and neutralized with 220.8 parts of a 48% aqueous solution of sodium hydroxide.
[0175]
Next, the single polymer 41 according to Example 5 ′ described above is added to the muddy water together with the dispersant for the drilling mud to produce the drilling mud according to the present embodiment, and 5% of cement is added to the mud for drilling. An experiment was conducted on the alkali resistance. In addition, as a dispersant for drilling mud, the total addition amount of the above-mentioned SS-B and sodium carbonate is 1 kg / m. ^Three The case where each was used together with the single polymer 61 and the case where both were used together with the single polymer 61 were examined.
[0176]
The experimental results are shown in Table 5 and FIG.
[0177]
[Table 5]

[0178]
As can be seen from these charts, when the drilling mud dispersing agent is used in combination with the single polymer 41 (3 cases other than the black circle), the drilling mud mud film forming agent is 3 kg / m. ^Three If it is added, the required wall-forming property can be obtained. On the other hand, when the single polymer 41 is used alone (in the case indicated by a black circle), the mud film forming agent for drilling mud is 5 kg / m. ^Three It can be seen that the required wall-forming property cannot be obtained unless it is added above.
[0179]
【The invention's effect】
As described above, according to the mud drilling mud production system and method according to the present invention, muddy water is prepared by kneading the peptized excavated sediment with clean water, and then the mud is used in the present invention. The drilling mud can be produced simply by adding the drilling mud film forming agent and the drilling mud dispersant.
[0180]
Therefore, it is not necessary to install a conventional mud production plant, and even at the start of construction, there is no need to purchase new drilling mud or procure from other sites. Can be produced quickly and easily.
[0181]
[Brief description of the drawings]
FIG. 1 is an overall view showing a mud production system for excavation according to the present embodiment.
FIG. 2 is a chemical structural formula showing a mud film forming agent for drilling mud used in the present embodiment.
FIG. 3 is an overall view showing a mud production system for excavating mud according to a modification.
FIG. 4 is a graph showing experimental results related to a mud production system and method for excavation according to the present embodiment.
FIG. 5 is a graph showing experimental results regarding a mud drilling system and method according to the present embodiment.
FIG. 6 is a chemical structural formula showing a mud film forming agent for drilling mud used in the second embodiment.
FIG. 7 is a graph showing the relationship between wall-forming property and weight average molecular weight in a mud film forming agent for drilling mud used in the second embodiment.
FIG. 8 is a graph showing the alkali resistance of a drilling mud dispersant used in the second embodiment.
[Explanation of symbols]
1 Mud production system for drilling mud
2 Compaction mixer (peptizer)
3 Mud tank
4 Muddy water storage tank
6 Storage tank
31 Drilling mud film forming agent
32 Sodium methacrylate (unsaturated carboxylate (a))
33 Methoxypolyethylene glycol methacrylate (monoester (b))
41 Single polymer ((co) polymer (x ′))
42 Sodium acrylate (unsaturated carboxylate (a))

Claims (7)

A muddy water storage tank for storing muddy water obtained by kneading peptized excavated soil and fresh water, and a storage tank for storing a muddy film forming agent for drilling muddy water added to the muddy water filled in the muddy water storage tank And forming the mud film forming agent for drilling mud in a liquid state and having a predetermined dispersibility and wall-forming property by combining with the fine particles of the drilling mud, forming the mud film for drilling mud Agent, unsaturated carboxylic acid and / or salt thereof (a), unsaturated carboxylic acid (b1) and the following general formula (1)
R (OA) _n OH (1)
R; hydrogen or a hydrocarbon group having 1 to 12 carbon atoms A; an alkylene group having 2 to 4 carbon atoms n; a monoester (b) of a hydroxyl group-containing compound (b2) represented by an integer of 1 to 100 Consists of a copolymer (x) as a unit, the mass percentage of the monoester (b) constituting the copolymer (x) is 1 to 40% and the number average of the copolymer (x) A mud drilling system for excavation characterized in that bentonite and CMC are made unnecessary as mud making materials by setting the molecular weight to 5000 to 100,000. A mud storage tank and peptized excavated soil and Shimizu storing the mud formed by kneading, storage tank mud film forming agent for drilling fluids that will be added to the mud filled in該泥water storage tank is stored And forming the mud film forming agent for drilling mud in a liquid state and having a predetermined dispersibility and wall-forming property by combining with the fine particles of the drilling mud, forming the mud film for drilling mud agent, by unsaturated carboxylic acid and / or a weight-average molecular weight Mw to a salt thereof (a) only a constituent unit is composed only of the 200000-3000000 (co) polymer (x '), bentonite and A mud production system for excavating mud water, characterized in that CMC is made unnecessary as a mud production material .   A liquid drilling mud dispersant is stored in the storage tank, and the drilling mud dispersant is a polyacrylate, polymethacrylate or copolymer thereof or carbonic acid having a weight average molecular weight Mw of 10,000 to 14,000. The mud drilling system for excavation according to claim 1 or 2, wherein the mud drilling system is constituted by at least one of sodium.   The mud drilling system for drilling according to any one of claims 1 to 3, further comprising a peptizer for producing the peptized excavated sediment. A mud drilling method for producing a drilling mud by adding a mud film forming agent for drilling mud to a mud obtained by kneading peptized drilling soil and fresh water, the mud film for drilling mud It is configured to have a predetermined dispersibility and wall-forming property by making the forming agent liquid and combining with fine particles of excavated sediment, and the mud film forming agent for drilling mud is used as unsaturated carboxylic acid and / or its Salt (a), unsaturated carboxylic acid (b1) and the following general formula (1)
R (OA) _n OH (1)
R; hydrogen or a hydrocarbon group having 1 to 12 carbon atoms A; an alkylene group having 2 to 4 carbon atoms n; a monoester (b) of a hydroxyl group-containing compound (b2) represented by an integer of 1 to 100 Consists of a copolymer (x) as a unit, the mass percentage of the monoester (b) constituting the copolymer (x) is 1 to 40% and the number average of the copolymer (x) A mud drilling method for drilling mud characterized in that bentonite and CMC are made unnecessary as mud drilling materials by setting the molecular weight to 5,000 to 100,000 . A mud drilling method for producing a drilling mud by adding a mud film forming agent for drilling mud to a mud obtained by kneading peptized drilling soil and fresh water, the mud film for drilling mud It is configured to have a predetermined dispersibility and wall-forming property by making the forming agent liquid and combining with fine particles of excavated sediment, and the mud film forming agent for drilling mud is used as unsaturated carboxylic acid and / or its by weight average molecular weight Mw to the structural unit only salt (a) is composed only of the 200,000 to 3,000,000 (co) polymer (x '), unnecessary that constitute the bentonite and CMC as Sakudoro material A mud making method for drilling mud.   A liquid drilling mud dispersant is stored in the storage tank, and the drilling mud dispersant is a polyacrylate, polymethacrylate or copolymer thereof or carbonic acid having a weight average molecular weight Mw of 10,000 to 14,000. The method for producing mud for excavation according to claim 5 or 6, comprising at least one of sodium.

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