JP4228337B2 - Mud management system - Google Patents

Description

【０１１３】
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。
【０１１４】

【０１１５】
【表２】

【０１１６】
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。
【０１１７】
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）。
【０１１８】
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。
【０１１９】
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。
【０１２０】
【表３】

【０１２１】
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。
【０１２２】
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。
【０１２３】
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。
【０１２４】
実験結果を図３及び図４に示す。
【０１２５】
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３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。
【０１２６】
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４(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。
【０１２７】
（第２実施形態）
【０１２８】
次に、第２実施形態に係る泥水管理システムを説明する。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。
【０１２９】
すなわち、第２実施形態に係る泥水管理システムも第１実施形態で説明した泥水管理システム１と同様、薬剤タンク２、炭酸ナトリウム水溶液タンク３、清水を供給可能な清水供給手段としての清水槽４及び混合槽５を備えるとともに、掘削溝１５内の泥水液位を計測する液面計１６と、掘削溝１５内の泥水の性状を計測する泥水計測装置１８と、液面計１６及び泥水計測装置１８に接続された制御装置１９とを備え、該制御装置は、図１(b)を参照して説明したように、液面計１６からの液位データ及び泥水計測装置１８からの泥水性状データを用いてポンプ６、ポンプ８及びポンプ１０を駆動制御できるようになっており、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実施形態に係る泥水管理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。
【０１３０】
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。
【０１３１】
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。
【０１３２】
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。
【０１３３】
図５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４２で構成してなる掘削泥水用泥膜形成剤４１を示してある。
【０１３４】
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。
【０１３５】
一方、掘削泥水用泥膜形成剤４１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。
【０１３６】
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４１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４１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。
【０１３７】
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。
【０１３８】
本実施形態に係る泥水管理システム１においては、薬剤タンク２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、炭酸ナトリウム水溶液タンク３に貯留された炭酸ナトリウム水溶液、及び清水槽４に貯留された清水とを、それぞれ配管７、配管９、配管１１を介して混合槽５に入れ混合液を作製するが、掘削泥水用泥膜形成剤や掘削泥水用分散剤といった薬剤や炭酸ナトリウム水溶液あるいは清水を混合槽５に入れるにあたっては、液面計１６によって掘削溝１５内の泥水液位を計測するとともに、泥水計測装置１８によって掘削溝１５内の泥水の性状を計測し、かかる計測結果に応じてポンプ６、ポンプ８、ポンプ１０を制御装置１９で制御し、薬剤及び清水の混合槽５への供給及び停止を制御する。
【０１３９】
すなわち、掘削が進行するにつれて掘削深度が下がるので、掘削溝内の液位を液面計１６で計測するとともにその計測データに応じてポンプ１０を制御装置１９で制御して掘削溝１５内に補充されるべき量の清水を混合槽５に供給することにより、泥水の液位を所定のレベルにあるいは許容範囲内に維持する。
【０１４０】
また、事前に予想した土質性状とは異なる場合、設計上の薬剤添加量では所望の造壁性や粘性を維持できないことがあるが、本実施形態においては、掘削溝１５内の泥水の性状を泥水計測装置１８で計測する。
【０１４１】
計測にあたっては、主として造壁性と粘性とを計測するようにすればよいが、必要に応じて泥水比重やｐＨを計測するようにしてもよい。
【０１４２】
次に、その計測データに応じてポンプ６、ポンプ８を制御装置１９で制御し、掘削溝１５内に添加される量の薬剤を混合槽５に供給する。
【０１４３】
ここで、添加される薬剤、すなわち掘削泥水用泥膜形成剤及び掘削泥水用分散剤並びに炭酸ナトリウム水溶液の量を決定するにあたっては、補充される清水はもちろん、すでに掘削溝１５内に満たされている掘削用泥水や土砂分離のために循環している循環泥水もすべて対象となるが、掘削溝１５内の泥水量については、図示しない掘削機に内蔵している深度計と液面計１６とから算出することができるし、土砂分離のために循環させている泥水量については、設計段階で算出可能である。
【０１４４】
次に、混合槽５内の混合液を中間貯留槽１３を介して掘削溝１５内に投入する。
【０１４５】
このようにすると、単位容積当たりの泥水中の薬剤含有量が調整されるとともに、より適切な含有量に調整された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孔壁に形成して該孔壁を安定させる。
【０１４６】
また、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するが、本実施形態で用いる掘削泥水用分散剤がカルシウムイオンによる分散性低下を抑制する。
【０１４７】
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。
【０１４８】
また、混合槽５から中間貯留槽１３への圧送、中間貯留槽１３から掘削溝１５への圧送については、あらたに作製された混合液がそのまま自動的に掘削溝１５に投入されるよう、配管、圧送ポンプ等を用いて適宜構成しておけばよい。
【０１４９】
泥水は、工事開始時においては、他の現場から入手した掘削用泥水や新規購入した掘削用泥水を使用できることはもちろん、本実施形態で用いる掘削泥水用泥膜形成剤は、劣化泥水の分散性や造壁性を改善して新たな掘削用泥水に再生する機能を有しているため、他の現場で劣化した廃泥水を使用することも可能である。
【０１５０】
以上説明したように、本実施形態に係る泥水管理システムによれば、掘削泥水用泥膜形成剤や掘削泥水用分散剤あるいは清水がすべて液状であるため、従来のベントナイト等の作泥材料とは異なり、混練のための手間や時間を要しないとともに、その結果として作泥作業と掘削溝１５への投入作業をタイムラグを生じることなく、ほぼ同時に行うことが可能となる。
【０１５１】
すなわち、本実施形態に用いる掘削泥水用泥膜形成剤や掘削泥水用分散剤を必要なときに必要なだけ、混合槽５及び中間貯留槽１３を介して迅速かつ容易に掘削溝１５内に投入し、これらを掘削溝１５内に解膠している掘削土の細粒分、例えば粘土やシルトを主成分とする７５μｍ以下の細粒分や、粘土を主成分とする１０μｍ以下の細粒分とともにあらたな掘削用泥水とすることができるため、結果として、掘削深度に合わせた迅速かつ容易な掘削用泥水の作製が可能となる。
【０１５２】
そして、かかる状況を前提とした上で、液面計１６によって掘削溝１５内の泥水液位を計測するとともに、泥水計測装置１８によって掘削溝１５内の泥水の性状を計測し、かかる計測結果に応じてポンプ６、ポンプ８、ポンプ１０を制御装置１９で制御し、薬剤及び清水の混合槽５への供給及び停止を制御するようにしたので、必要な作泥作業を自動化することが可能となり、掘削工事自体の工期短縮及びコスト低減を図ることができるとともに、従来のように経験や熟練度とは関係なく、掘削溝１５内に満たされた掘削用泥水の造壁性と粘性とを常に最適な状態に維持することが可能となる。
【０１５３】
本実施形態では、炭酸ナトリウム水溶液タンク３を設けたが、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、かかる炭酸ナトリウム水溶液タンク３並びにそれに付随するポンプ８及び配管１１を省略してもよい。かかる構成においては、制御装置１９の制御対象は、ポンプ６及びポンプ１０のみとなる。
【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併用することを前提とし、これらを薬剤タンク２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薬剤タンク２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、薬剤タンク２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、薬剤タンク２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。
【０１５５】
また、本実施形態では、混合槽５で作製された混合液をいったん中間貯留槽１３に貯留するようにしたが、かかる中間貯留槽１３を省略して直接、掘削溝１５内に投入するようにしてもよいことは言うまでもない。かかる場合には、混合液吐出管１４は、混合槽５に直接接続すればよい。
【０１５６】
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してから掘削溝１５に投入することを前提として、混合槽５を備えるようにしたが、これらを掘削溝１５に直接添加しても上述した掘削用泥水の品質管理を行うことに支障がないのであれば、混合槽５を省略し、薬剤タンク２に接続された配管７及び清水槽４に接続された配管１１を掘削溝１５内に直接、連通させるようにしてもよい。なお、かかる場合においても、制御装置１９によるポンプ６及びポンプ１０への制御操作は上述した実施形態と同様であり、その作用効果についてはここではその説明を省略する。
【０１５７】
また、本実施形態では特に言及しなかったが、中間貯留槽１３として、従来から使用されている回収槽、すなわちコンクリート置換された後の掘削用泥水を回収貯留するための槽で代用してもよいし、土砂分離のための循環経路に設置された任意の槽、例えば循環槽、泥水貯留槽等で代用してもよい。
【０１５８】
また、本実施形態では、掘削溝１５内の泥水を計測のために仮貯留する計測槽１７を設けたが、これを省略し、掘削溝１５内の泥水を直接引き抜くようにしてもよいし、土砂分離のための循環経路に設置された任意の槽、例えば循環槽、泥水貯留槽等から引き抜いてもよいことは言うまでもない。
【０１５９】
【実施例】
次に、本実施形態で用いる掘削泥水用泥膜形成剤４１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。
【０１６０】
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４１を製造した。
【０１６１】
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４１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。
【０１６２】
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。
【０１６３】
但し、カラムは下記のものを用いる。
カラム ；TSKgel α-3000 + TSKgel α-6000
【０１６４】
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。
【０１６５】
また、単一重合体４１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。
【０１６６】
【表４】

【０１６７】
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４１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４１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。
【０１６８】
また、図６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。
【０１６９】
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。
【０１７０】
単一重合体４１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。
【０１７１】
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４１と併用した場合と、両方を単一重合体４１と併用した場合について調べた。
【０１７２】
実験結果を表５及び図７に示す。
【０１７３】
【表５】

【０１７４】
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。
【０１７５】
【発明の効果】
以上述べたように、本発明に係る泥水管理システムによれば、掘削泥水用泥膜形成剤や掘削泥水用分散剤あるいは清水がすべて液状であるため、従来のベントナイト等の作泥材料とは異なり、混練のための手間や時間を要しないとともに、その結果として作泥作業と掘削孔への投入作業をタイムラグを生じることなく、ほぼ同時に行うことが可能となる。
【０１７６】
すなわち、本発明に用いる掘削泥水用泥膜形成剤や掘削泥水用分散剤を必要なときに必要なだけ、迅速かつ容易に掘削孔内に投入し、これらを掘削孔内に解膠している掘削土の細粒分とともにあらたな掘削用泥水とすることができるため、結果として、掘削深度に合わせた迅速かつ容易な掘削用泥水の作製が可能となる。
【０１７７】
そして、かかる状況を前提とした上で、液面計によって掘削孔内の泥水液位を計測するとともに、泥水計測装置によって掘削孔内の泥水の性状を計測し、かかる計測結果に応じて薬剤用吐出制御手段及び清水用吐出制御手段を制御装置で制御し、薬剤及び清水の掘削孔への供給及び停止を制御するようにしたので、作泥作業を自動化することが可能となり、掘削工事自体の工期短縮及びコスト低減を図ることができるとともに、従来のように経験や熟練度とは関係なく、掘削孔内に満たされた掘削用泥水の造壁性と粘性とを常に最適な状態に維持することが可能となる。
【０１７８】
【図面の簡単な説明】
【図１】本実施形態に係る泥水管理システムを示した図。
【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】本実施形態に係る泥水管理システムに関する実験結果を示したグラフ。
【図４】同じく本実施形態に係る泥水管理システムに関する実験結果を示したグラフ。
【図５】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６】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７】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 泥水管理システム
２ 薬剤タンク
４ 清水槽（清水供給手段）
５ 混合槽
１５ 掘削溝（掘削孔）
１６ 液面計
１８ 泥水計測装置
１９ 制御装置
２１ 掘削泥水用泥膜形成剤
２２ メタクリル酸ナトリウム塩（不飽和カルボン酸塩（ａ））
２３ 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
The present invention relates to a muddy water management system used in a muddy water method such as an underground continuous wall method and an in-situ concrete pile method.
[0002]
[Prior art]
In the mud construction methods such as the underground continuous wall construction method and the cast-in-place concrete pile construction method, so-called excavation mud is used, and such excavation mud has good wall-forming properties in order to stabilize the 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. In addition, it is required to have cement resistance because underwater concrete placement is performed after excavation is completed.
[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. In such a drilling mud, bentonite and the like are well dispersed in the mud, so that the low viscosity is maintained, and the dispersed bentonite and the like forms a good mud cake on the groove wall and is stopped by the mud cake. It becomes possible to ensure the stability of the water 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, it is not only necessary to knead them using a kneading mixer, but the above-mentioned mud-making materials are inherently dissolved in water. Since it is difficult, melting work using a kneading mixer requires time and effort.
[0005]
Therefore, in situations where the depth increases as the excavation progresses and a larger amount of drilling mud must be supplied continuously and quickly into the excavation groove, mud production is performed in a separate process from the excavation work. I have to do it. In other words, after setting up a large-scale mud plant capable of handling deep drilling, predicting the drilling speed at the site, and taking into account the time lag caused by the time required for kneading work Thus, there has been a problem that the drilling mud must be prepared so as not to cause delay in the drilling work, and considerable skill and experience are required for the management of such mud work.
[0006]
The present invention has been made in view of the above-described circumstances, and an object thereof is to provide a mud management system that can automate mud production and mud management without requiring skill and experience.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, a mud management system according to the present invention is a drilling mud having a predetermined dispersibility and wall-forming property by being combined with fine particles of excavated soil as described in claim 1. A chemical tank that stores a mud film forming agent, fresh water supply means that can supply fresh water, the mud film forming agent for drilling mud and the fresh water are mixed to produce a mixed liquid, and the mixed liquid is made into the drilling hole. A mixing tank to be supplied; a discharge control means for medicine provided on the discharge side of the medicine tank; and a fresh water provided on the discharge side of the fresh water supply means and capable of controlling the discharge. Discharge control means, a liquid level meter for measuring the level of the muddy water in the borehole, a mud measuring device for measuring the property of the mud in the borehole, and the liquid level meter and the mud measuring device. And a control device. The location, By controlling the fresh water discharge control means using the liquid level data from the liquid level gauge, an amount of fresh water to be refilled in the excavation hole is supplied to the mixing tank so that the muddy water level is predetermined. Of the amount added to the excavation hole by controlling the drug discharge control means using the muddy water state data from the muddy water measuring device. It was configured to supply the medicine to the mixing tank Is.
[0008]
Further, the mud management system according to the present invention is a mud film forming agent for drilling mud, which is liquid and has a predetermined dispersibility and wall-forming property by being combined with fine particles of the drilling earth and sand. A chemical tank that stores water, a fresh water supply means that can supply fresh water, a discharge control means for medicine that is provided on the discharge side of the chemical tank and that can control the discharge thereof, and is provided on the discharge side of the fresh water supply means. Discharge control means for fresh water capable of controlling discharge, a liquid level meter for measuring the level of muddy water in the excavation hole, a mud measurement device for measuring properties of the mud in the excavation hole, the liquid level gauge, A control device connected to the muddy water measuring device, and the control device, By controlling the fresh water discharge control means using the liquid level data from the liquid level gauge, an amount of fresh water to be replenished in the excavation hole is supplied to the excavation hole, and the mud liquid level is predetermined. Of the amount added to the excavation hole by controlling the drug discharge control means using the muddy water state data from the muddy water measuring device. It was configured so that the drug was supplied to the borehole Is.
[0009]
Moreover, the mud management system which concerns on this invention is the said mud film formation agent for drilling mud, unsaturated carboxylic acid and / or its salt (a), unsaturated carboxylic acid (b1), and 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.
[0010]
Further, in the mud management system according to the present invention, 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.
In addition, the mud management system according to the present invention stores a liquid drilling mud dispersant in the chemical tank, and the drilling mud dispersant contains a polyacrylate, polyacrylic acid salt having a weight average molecular weight Mw of 10,000 to 14,000. It is composed of at least one of a methacrylate or a copolymer thereof or sodium carbonate.
[0011]
In the mud excavation method such as the underground continuous wall method and the cast-in-place concrete pile method, in order to stabilize the hole wall, a high quality mud film (mud cake) with a small amount of drainage is formed on the hole wall, and the mud water pressure is transferred to the hole wall. For this purpose, a mud-making material having wall-forming properties such as bentonite, CMC, and polymer agent has been indispensable in the past.
[0012]
However, in view of the above-mentioned problems that these mud-making materials have to be used, the present applicant is not able to use these mud-making materials, but only using excavated soil and water. As a result of various experiments, we have focused on whether it is possible to create muddy water for excavation, especially whether it is possible to create muddy water for excavation suitable for continuous underground walls and on-site concrete pile construction methods. We have developed a dispersant for drilling mud and a new mud film forming agent for drilling mud that can secure the wall-forming property at the hole wall with water and water alone.
[0013]
Furthermore, the present applicant noticed that not only such a drilling mud dispersing agent but also a newly developed mud film forming agent for drilling mud is in a liquid state. It is a success.
[0014]
That is, in the mud management system according to claim 1, the mud film forming agent for drilling mud stored in the chemical tank and the fresh water supplied from the fresh water supply means are put into a mixing tank to produce a mixed solution. When the mud film forming agent for drilling mud and fresh water are put into the mixing tank, the level of the mud water in the drilling hole is measured by a liquid level gauge, and the property of the mud water in the drilling hole is measured by a mud measuring device, According to the measurement result, the medicine discharge control means and the fresh water discharge control means are controlled by the control device to control supply and stop of the medicine and fresh water to the mixing tank.
[0015]
That is, as the excavation progresses, the excavation depth decreases, so the liquid level in the excavation hole is measured with a level gauge and the fresh water discharge control means is controlled by the control device in accordance with the measurement data to replenish the excavation hole. By supplying an amount of fresh water to be mixed to the mixing tank, the level of the muddy water is maintained at a predetermined level or within an allowable range.
[0016]
In addition, when it is different from the predicted soil properties, the desired wall-forming property and viscosity may not be maintained with the amount of chemical added in the design, but in the invention according to claim 1, the muddy water in the drilling hole may not be maintained. The property is measured by the muddy water measuring device, and the discharge control means for the drug is controlled by the control device according to the measurement data, and the amount of the drug added into the excavation hole is supplied to the mixing tank. And the chemical | medical agent content in the muddy water per unit volume is adjusted, and muddy water wall-forming property and viscosity are maintained in a desired range.
[0017]
In addition, in determining the amount of chemicals to be added, not only the fresh water to be replenished but also all the mud for excavation already filled in the borehole and the circulating mud that is circulating for sediment separation are included. However, the amount of muddy water in the borehole can be calculated from the depth gauge and level gauge built in the excavator, and the amount of muddy water circulated for sediment separation is determined at the design stage. It can be calculated.
[0018]
Moreover, what is necessary is just to comprise suitably about the liquid mixture produced in the mixing tank using piping, a pressure feed pump, etc. so that it may be automatically pressure-fed in an excavation hole.
[0019]
In the mud management system according to claim 2, the drilling mud film forming agent stored in the chemical tank and the fresh water supplied from the fresh water supply means are directly supplied to the drilling hole. When supplying mud film forming agent and fresh water to the drilling hole, measure the liquid level in the drilling hole with a level gauge and measure the properties of the mud in the drilling hole with a mud measuring device. Accordingly, the medicine discharge control means and the fresh water discharge control means are controlled by the control device to control supply and stop of the medicine and fresh water into the excavation hole.
[0020]
That is, as the excavation progresses, the excavation depth decreases. Therefore, the liquid level in the excavation hole is measured by the liquid level gauge, and the discharge control means for fresh water is controlled by the control device according to the measurement data, and the amount to be replenished By supplying the fresh water into the borehole, the level of mud water is maintained at a predetermined level or within an allowable range.
[0021]
In addition, if the soil properties are different from those predicted in advance, it may not be possible to maintain the desired wall-forming property and viscosity with the amount of the chemical added in the design. The property is measured by the muddy water measuring device, and the medicine discharge control means is controlled by the control device in accordance with the measurement data, and an amount of the medicine to be added is supplied to the excavation hole. And the chemical | medical agent content in the muddy water per unit volume is adjusted, and muddy water wall-forming property and viscosity are maintained in a desired range.
[0022]
In addition, in determining the amount of chemicals to be added, not only the fresh water to be replenished but also all the mud for excavation already filled in the borehole and the circulating mud that is circulating for sediment separation are included. However, the amount of muddy water in the borehole can be calculated from the depth gauge and level gauge built in the excavator, and the amount of muddy water circulated for sediment separation is determined at the design stage. It can be calculated.
[0023]
At the start of construction, the mud can be excavated mud obtained from other sites or newly purchased excavated mud. Since it has a function of improving the dispersibility and wall-forming property and regenerating it into a new excavation mud, it is possible to use waste mud that has deteriorated at other sites.
[0024]
On the other hand, the mud film forming agent for drilling mud used in the present invention has the function of ensuring the wall-forming property at the hole wall only with the excavated soil and water, and ensuring its stability. Once excavation work is started, no powdered mud materials such as bentonite, CMC, and polymer agent, which have been indispensable in the past, are required.
[0025]
Since the mud film forming agent for drilling mud and the fresh water are all liquid, it is possible to quickly and easily put the required amount into the drilling hole when necessary. And since these become the new mud for drilling together with the fine particles of the excavated soil peptized in the borehole, as a result, it is possible to quickly and easily produce the mud for drilling according to the depth of excavation. .
[0026]
The mud film forming agent for drilling mud used in the present invention is in any form as long as it is liquid and is configured to have a predetermined dispersibility and wall-forming property by being combined with fine particles of excavated earth and sand. For example, the mud film forming agent for drilling mud may be 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 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. It is possible.
[0027]
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.
[0028]
That is, in the underground continuous wall method, etc., calcium ions are eluted from the concrete along with the circulation use of the drilling mud, and the calcium ion concentration in the mud increases. If the dispersant for muddy water is used in combination, the dispersibility degradation due to calcium ions is suppressed by the dispersant for drilling muddy water, so if it is a muddy water for drilling obtained in the present invention, this is the underground continuous wall construction method Even if it is circulated and used, the wall-forming property and low viscosity are maintained well.
[0029]
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.
[0030]
The medicine discharge control means and the fresh water discharge control means may be anything as long as they can be supplied to and stopped from the mixing tank and the excavation hole. For example, it may be configured by a pressure feed pump or an opening / closing valve. .
[0031]
The liquid level gauge may be anything as long as it can measure the liquid level in the excavation hole, but it is conceivable to use a liquid level gauge constituted by a non-contact type, for example, an ultrasonic sensor.
[0032]
The fresh water supply means may be, for example, a fresh water tank or water supply that can store fresh water.
[0033]
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.
[0034]
As the solvent, for example, water, isopropyl alcohol, toluene, ethylene dichloride, methyl ethyl ketone, or a mixture thereof can be used.
[0035]
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.
[0036]
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.
[0037]
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.
[0038]
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).
[0039]
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.
[0040]
In the general ester (b), R is hydrogen or an alkylene group in the general formula (1), but in order to ensure good wall-forming properties, it is usually hydrogen or 1 to 12 carbons, and further 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.
[0041]
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.
[0042]
(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.
[0043]
Examples of the aliphatic dihydric alcohol having 2 to 4 carbon atoms include ethylene glycol, propylene glycol, and 1,4-butanediol.
[0044]
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
[0045]
Examples of phenols include phenol and ethylphenol. Examples of the araliphatic alcohol include benzyl alcohol.
[0046]
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.
[0047]
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.
[0048]
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).
[0049]
(C1) Amide group-containing ethylenically unsaturated monomer: (meth) acrylamide, N-methylol (meth) acrylamide, etc.
[0050]
(C2) (Meth) acrylic acid alkyl esters (alkyl group having 1 to 12 carbon atoms): methyl (meth) acrylate, butyl (meth) acrylate, etc.
[0051]
(C3) Ethylenically unsaturated monomer having a hydroxyl group: hydroxyalkyl (1 to 4 carbon atoms) (meth) acrylate [eg, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, etc.]
[0052]
(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.
[0053]
(C5) Quaternary ammonium group-containing ethylenically unsaturated monomer: (meth) acryloyloxyethyltrimethylammonium chloride, (meth) acryloyloxyethyldimethylbenzylammonium chloride, etc.
[0054]
Among these (c1) to (c5), preferred are (c2) to (c4).
[0055]
Moreover, the mass% of the other monomer (c) unit which comprises copolymer (X) is 30% or less normally, Preferably it is 20% or less.
[0063]
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.
[0064]
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.
[0065]
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.
[0069]
In addition, the mud film forming agent for drilling mud according to claim 3 may be used in combination with the mud film forming agent for drilling mud according to claim 2 in an arbitrary ratio (for example, a mass ratio of 99: 1 to 1:99). Is possible.
[0070]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of a muddy water management system according to the present invention will be described below 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.
[0071]
(First embodiment)
[0072]
FIG. 1 (a) is an overall view showing a muddy water management system according to the present embodiment. As can be seen from the figure, the muddy water management system 1 according to the present embodiment includes a chemical tank 2, a sodium carbonate aqueous solution tank 3, a fresh water tank 4 and a mixing tank 5 as fresh water supply means capable of supplying fresh water.
[0073]
In the chemical tank 2, a mud film forming agent for drilling mud and a dispersant for drilling mud used in the present embodiment are stored, and a pump 6 serving as a chemical discharge control means connected to the discharge side of the tank is provided. By driving, the dispersant for drilling mud and the mud film forming agent for drilling mud can be pumped to the mixing tank 5 via the pipe 7.
[0074]
Similarly, a pump 8 is also connected to the discharge side of the sodium carbonate aqueous solution tank 3, and the sodium carbonate aqueous solution can be pumped to the mixing tank 5 through the pipe 9 by driving the pump.
[0075]
On the other hand, fresh water is stored in the fresh water tank 4, and the fresh water is pumped to the mixing tank 5 through the pipe 11 by driving a pump 10 as a fresh water discharge control means connected to the discharge side of the tank. It can be done.
[0076]
The mixing tank 5 mixes the mud film-forming agent for drilling mud, the dispersant for drilling mud, and fresh water to produce a mixed solution. The mixing tank 5 may be provided with a stirring mechanism (not shown) as required.
[0077]
Here, the mixing tank 5 is connected to the intermediate storage tank 13 through the pipe 12 and is used for constructing a continuous underground wall that is an excavation hole through the mixed liquid discharge pipe 14 connected to the intermediate storage tank. Is connected to the inside of the excavation groove 15, and after the mixed liquid prepared in the mixing tank 5 is temporarily stored in the intermediate storage tank 13, the excavation groove for constructing the underground continuous wall through the mixed liquid discharge pipe 14. 15, and the mixed liquid that has been put into the excavation groove 15 as a new excavation mud together with the fine particles of the excavated soil peptized in the excavation groove 15. The drilling mud will be replenished.
[0078]
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).
[0079]
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.
[0080]
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.
[0081]
In addition, about a number average molecular weight, it shall measure with a gel permeation chromatograph.
[0082]
FIG. 2 shows an example of a mud film forming agent 21 for drilling mud, in which the unsaturated carboxylic acid and / or its salt (a) is composed of sodium methacrylate 22 and the monoester (b) is composed of methoxypolyethylene glycol methacrylate 23. Is a chemical structural formula (chemical formula) shown as
[0083]
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.
[0084]
On the other hand, the muddy water management system 1 according to the present embodiment measures the level of the muddy water level in the excavation groove 15 and the property of the muddy water in the excavation groove 15 as shown in FIG. And a control device 19 connected to the liquid level meter 16 and the muddy water measurement device 18, which can be understood from the liquid level meter 16 as well understood in FIG. The pump 6, the pump 8 and the pump 10 can be driven and controlled using the liquid level data and the muddy water state data from the muddy water measuring device 18.
[0085]
The control device 19 can be configured using a personal computer as shown in FIG. 1, for example.
[0086]
The muddy water measuring device 18 performs measurement on the muddy water pumped up from the excavation groove 15 to the measurement tank 17, and the muddy water in the measurement tank 17 is returned to the excavation groove 15 continuously or at any time. The configuration to do is conceivable.
[0087]
In the mud management system 1 according to the present embodiment, the mud film forming agent for drilling mud and the dispersant for drilling mud stored in the chemical tank 2, the sodium carbonate aqueous solution stored in the sodium carbonate aqueous solution tank 3, and the fresh water tank 4 The fresh water stored in the tank is put into the mixing tank 5 through the pipe 7, the pipe 9 and the pipe 11, respectively, to prepare a mixed solution. However, a chemical such as a mud film forming agent for drilling mud and a dispersant for drilling mud, sodium carbonate When putting the aqueous solution or fresh water into the mixing tank 5, the level of the muddy water in the excavation groove 15 is measured by the liquid level gauge 16, and the property of the mud in the excavation groove 15 is measured by the muddy water measuring device 18. Accordingly, the pump 6, the pump 8, and the pump 10 are controlled by the control device 19, and the supply and stop of the medicine and fresh water to the mixing tank 5 are controlled.
[0088]
That is, as the excavation progresses, the excavation depth decreases, so the liquid level in the excavation groove is measured by the liquid level gauge 16 and the pump 10 is controlled by the control device 19 according to the measurement data to replenish the excavation groove 15. By supplying an amount of fresh water to be mixed to the mixing tank 5, the level of the muddy water is maintained at a predetermined level or within an allowable range.
[0089]
In addition, in the case where the soil property is different from the predicted soil property, the desired wall-forming property and viscosity may not be maintained with the designed chemical addition amount, but in this embodiment, the property of the muddy water in the excavation groove 15 is Measure with the muddy water measuring device 18.
[0090]
In measurement, the wall-forming property and the viscosity may be mainly measured, but the muddy water specific gravity and pH may be measured as necessary.
[0091]
Next, the pump 6 and the pump 8 are controlled by the control device 19 according to the measurement data, and an amount of the chemical added into the excavation groove 15 is supplied to the mixing tank 5.
[0092]
Here, in determining the amount of chemicals to be added, that is, the mud film forming agent for drilling mud and the dispersant for drilling mud, and the sodium carbonate aqueous solution, the fresh water to be replenished is already filled in the drilling groove 15. The drilling mud and the circulating mud circulating for soil separation are all targeted, but the amount of mud in the excavation groove 15 is determined by the depth gauge and the liquid level gauge 16 incorporated in the excavator (not shown). The amount of muddy water circulated for sediment separation can be calculated at the design stage.
[0093]
Next, the mixed liquid in the mixing tank 5 is put into the excavation groove 15 through the intermediate storage tank 13.
[0094]
In this way, the chemical content in the mud per unit volume is adjusted, and the mud film forming agent for drilling mud and the dispersant for drilling mud adjusted to a more appropriate content can be used in conventional bentonite, etc. Instead, it is dispersed in the muddy water with fine particles of 10 μm or less mainly composed of clay, for example, and maintains a low viscosity. ) Is formed on the hole wall to stabilize the hole wall.
[0095]
In addition, calcium ions are eluted from the concrete as the drilling mud is circulated and the calcium ion concentration in the mud increases, but the dispersant for drilling mud used in this embodiment suppresses the decrease in dispersibility due to calcium ions. .
[0096]
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.
[0097]
In addition, with respect to the pressure feeding from the mixing tank 5 to the intermediate storage tank 13 and the pressure feeding from the intermediate storage tank 13 to the excavation groove 15, a pipe is prepared so that the newly prepared mixed liquid is automatically introduced into the excavation groove 15 as it is. It may be configured appropriately using a pressure feed pump or the like.
[0098]
At the beginning of construction, the mud can be excavated mud obtained from other sites or newly purchased excavated mud. In addition, it has the function of improving the wall construction and regenerating to a new excavation mud, so it is also possible to use waste mud that has deteriorated at other sites.
[0099]
As described above, according to the mud management system according to the present embodiment, the mud film forming agent for drilling mud, the dispersant for drilling mud, or the fresh water are all in liquid form. In contrast, it does not require labor and time for kneading, and as a result, it is possible to perform the mud making operation and the input operation to the excavation groove 15 almost simultaneously without causing a time lag.
[0100]
That is, when necessary, the mud film forming agent for drilling mud and the dispersant for drilling mud used in this embodiment are quickly and easily introduced into the drilling groove 15 through the mixing tank 5 and the intermediate storage tank 13. The fine portion of the excavated soil in which these are peptized in the excavation groove 15, for example, the fine particle portion of 75 μm or less mainly composed of clay or silt, or the fine particle portion of 10 μm or less mainly composed of clay At the same time, a new excavation mud can be obtained, and as a result, the excavation mud can be quickly and easily produced in accordance with the excavation depth.
[0101]
On the assumption of such a situation, the liquid level gauge 16 measures the level of the muddy water in the excavation groove 15 and the mud measurement device 18 measures the property of the mud in the excavation groove 15 to obtain the measurement result. Accordingly, the pump 6, the pump 8 and the pump 10 are controlled by the control device 19 so as to control the supply and stop of the chemical and fresh water to the mixing tank 5, so that it becomes possible to automate the necessary mud production work. In addition to shortening the construction period and cost of the excavation work itself, the wall construction and viscosity of the excavation mud filled in the excavation groove 15 are always maintained regardless of experience and skill level as in the past. It becomes possible to maintain the optimum state.
[0102]
In this embodiment, the sodium carbonate aqueous solution tank 3 is provided. However, if the dispersibility reduction at the time of cement mixing can be sufficiently suppressed by the drilling mud dispersant used in this embodiment, the sodium carbonate aqueous solution tank is used. 3 and the accompanying pump 8 and pipe 11 may be omitted. In such a configuration, the control target of the control device 19 is only the pump 6 and the pump 10.
[0103]
Further, in this embodiment, it is assumed that the mud film forming agent for drilling mud and the dispersant for drilling mud are used in combination, and these are stored in the chemical tank 2, but these chemicals are all constant. Since it has dispersibility and wall-forming property, depending on the case, either one may be used alone. On the other hand, when using a mud film forming agent for drilling mud and a dispersing agent for drilling mud, they may be stored in the chemical tank 2 in a mixed state, but they should be stored in dedicated tanks. It doesn't matter. In this case, a total of two drug tanks 2 are provided.
[0104]
In the present embodiment, the liquid mixture prepared in the mixing tank 5 is once stored in the intermediate storage tank 13. However, the intermediate storage tank 13 is omitted and the mixed liquid is directly put into the excavation groove 15. Needless to say. In such a case, the mixed liquid discharge pipe 14 may be directly connected to the mixing tank 5.
[0105]
Further, in this embodiment, the mixing tank 5 is provided on the assumption that the mud film forming agent for drilling mud and the dispersant for drilling mud are diluted and then introduced into the drilling groove 15. If there is no hindrance to the quality control of the drilling mud described above even if added directly to 15, the mixing tank 5 is omitted, and the pipe 7 connected to the chemical tank 2 and the fresh water tank 4 are connected. The pipe 11 may be directly communicated with the excavation groove 15. Even in such a case, the control operation to the pump 6 and the pump 10 by the control device 19 is the same as that in the above-described embodiment, and the description of the operation and effect is omitted here.
[0106]
Although not specifically mentioned in the present embodiment, the intermediate storage tank 13 may be replaced with a conventionally used recovery tank, that is, a tank for recovering and storing the excavated mud after the concrete replacement. Alternatively, any tank installed in the circulation path for earth and sand separation, such as a circulation tank or a muddy water storage tank, may be substituted.
[0107]
Further, in the present embodiment, the measurement tank 17 for temporarily storing the muddy water in the excavation groove 15 is provided, but this may be omitted, and the muddy water in the excavation groove 15 may be directly drawn out. It goes without saying that any tank installed in the circulation path for earth and sand separation, for example, a circulation tank, a muddy water storage tank or the like may be extracted.
[0108]
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.
[0109]
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.
[0110]
【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.
[0111]
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.
[0112]
[Table 1]

[0113]
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.
[0114]

[0115]
[Table 2]

[0116]
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.
[0117]
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).
[0118]
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.
[0119]
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.
[0120]
[Table 3]

[0121]
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.
[0122]
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.
[0123]
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.
[0124]
The experimental results are shown in FIGS.
[0125]
First, FIG. 3 shows the experimental results when no cement is added to the excavation mud described above. 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.
[0126]
Next, the experimental results when 1% and 5% of cement are added to the excavation mud are shown in FIGS. 4 (a) and 4 (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%.
[0127]
(Second Embodiment)
[0128]
Next, a muddy water management system 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.
[0129]
That is, the muddy water management system according to the second embodiment is the same as the muddy water management system 1 described in the first embodiment, the chemical tank 2, the sodium carbonate aqueous solution tank 3, the fresh water tank 4 as fresh water supply means capable of supplying fresh water, and While equipped with the mixing tank 5, the liquid level meter 16 which measures the muddy water level in the excavation groove 15, the mud measurement device 18 which measures the property of the mud in the excavation groove 15, the liquid level meter 16 and the mud measurement device 18 The control device 19 is connected to the control device 19, and as described with reference to FIG. 1 (b), the control device receives the liquid level data from the level gauge 16 and the muddy water condition data from the muddy water measuring device 18. The pump 6, the pump 8 and the pump 10 can be driven and controlled, and the muddy water management according to the first embodiment is different except that the chemical composition of the mud film forming agent for drilling mud and the dispersant for drilling mud is different. System and Formation and is exactly the same, therefore, no further detailed description is omitted here.
[0130]
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.
[0131]
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.
[0132]
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.
[0133]
FIG. 5 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 42. A mud film forming agent 41 for drilling mud is shown.
[0134]
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.
[0135]
On the other hand, the mud film forming agent 41 for drilling mud is preferably used with a concentration of 20 to 30% by mass added to the mud, but in such a concentration range, when the weight average molecular weight Mw exceeds 1,000,000, When it is added to muddy water, it is not necessarily excellent in workability.
[0136]
Therefore, it is desirable that the weight average molecular weight Mw of the mud film forming agent 41 for drilling mud is set to 500,000 to 1,000,000 from the viewpoint of the addition workability. Further, it is optimal to set the weight average molecular weight Mw of the mud film forming agent 41 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.
[0137]
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.
[0138]
In the mud management system 1 according to the present embodiment, the mud film forming agent for drilling mud and the dispersant for drilling mud stored in the chemical tank 2, the sodium carbonate aqueous solution stored in the sodium carbonate aqueous solution tank 3, and the fresh water tank 4 The fresh water stored in the tank is put into the mixing tank 5 through the pipe 7, the pipe 9 and the pipe 11, respectively, to prepare a mixed solution. However, a chemical such as a mud film forming agent for drilling mud and a dispersant for drilling mud, sodium carbonate When putting the aqueous solution or fresh water into the mixing tank 5, the level of the muddy water in the excavation groove 15 is measured by the liquid level gauge 16, and the property of the mud in the excavation groove 15 is measured by the muddy water measuring device 18. Accordingly, the pump 6, the pump 8, and the pump 10 are controlled by the control device 19, and the supply and stop of the medicine and fresh water to the mixing tank 5 are controlled.
[0139]
That is, as the excavation progresses, the excavation depth decreases, so the liquid level in the excavation groove is measured by the liquid level gauge 16 and the pump 10 is controlled by the control device 19 according to the measurement data to replenish the excavation groove 15. By supplying an amount of fresh water to be mixed to the mixing tank 5, the level of the muddy water is maintained at a predetermined level or within an allowable range.
[0140]
In addition, in the case where the soil property is different from the predicted soil property, the desired wall-forming property and viscosity may not be maintained with the designed chemical addition amount, but in this embodiment, the property of the muddy water in the excavation groove 15 is Measure with the muddy water measuring device 18.
[0141]
In measurement, the wall-forming property and the viscosity may be mainly measured, but the muddy water specific gravity and pH may be measured as necessary.
[0142]
Next, the pump 6 and the pump 8 are controlled by the control device 19 according to the measurement data, and an amount of the chemical added into the excavation groove 15 is supplied to the mixing tank 5.
[0143]
Here, in determining the amount of chemicals to be added, that is, the mud film forming agent for drilling mud and the dispersant for drilling mud, and the sodium carbonate aqueous solution, the fresh water to be replenished is already filled in the drilling groove 15. The drilling mud and the circulating mud circulating for soil separation are all targeted, but the amount of mud in the excavation groove 15 is determined by the depth gauge and the liquid level gauge 16 incorporated in the excavator (not shown). The amount of muddy water circulated for sediment separation can be calculated at the design stage.
[0144]
Next, the mixed liquid in the mixing tank 5 is put into the excavation groove 15 through the intermediate storage tank 13.
[0145]
In this way, the chemical content in the mud per unit volume is adjusted, and the mud film forming agent for drilling mud and the dispersant for drilling mud adjusted to a more appropriate content can be used in conventional bentonite, etc. Instead, it is dispersed in the muddy water with fine particles of 10 μm or less mainly composed of clay, for example, and maintains a low viscosity. ) Is formed on the hole wall to stabilize the hole wall.
[0146]
In addition, calcium ions are eluted from the concrete as the drilling mud is circulated and the calcium ion concentration in the mud increases, but the dispersant for drilling mud used in this embodiment suppresses the decrease in dispersibility due to calcium ions. .
[0147]
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.
[0148]
In addition, with respect to the pressure feeding from the mixing tank 5 to the intermediate storage tank 13 and the pressure feeding from the intermediate storage tank 13 to the excavation groove 15, a pipe is prepared so that the newly prepared mixed liquid is automatically introduced into the excavation groove 15 as it is. It may be configured appropriately using a pressure feed pump or the like.
[0149]
At the beginning of construction, the mud can be excavated mud obtained from other sites or newly purchased excavated mud. In addition, it has the function of improving the wall construction and regenerating to a new excavation mud, so it is also possible to use waste mud that has deteriorated at other sites.
[0150]
As described above, according to the mud management system according to the present embodiment, the mud film forming agent for drilling mud, the dispersant for drilling mud, or the fresh water are all in liquid form. In contrast, it does not require labor and time for kneading, and as a result, it is possible to perform the mud making operation and the input operation to the excavation groove 15 almost simultaneously without causing a time lag.
[0151]
That is, when necessary, the mud film forming agent for drilling mud and the dispersant for drilling mud used in this embodiment are quickly and easily introduced into the drilling groove 15 through the mixing tank 5 and the intermediate storage tank 13. The fine portion of the excavated soil in which these are peptized in the excavation groove 15, for example, the fine particle portion of 75 μm or less mainly composed of clay or silt, or the fine particle portion of 10 μm or less mainly composed of clay At the same time, a new excavation mud can be obtained, and as a result, the excavation mud can be quickly and easily produced in accordance with the excavation depth.
[0152]
On the assumption of such a situation, the liquid level gauge 16 measures the level of the muddy water in the excavation groove 15 and the mud measurement device 18 measures the property of the mud in the excavation groove 15 to obtain the measurement result. Accordingly, the pump 6, the pump 8 and the pump 10 are controlled by the control device 19 so as to control the supply and stop of the chemical and fresh water to the mixing tank 5, so that it becomes possible to automate the necessary mud production work. In addition to shortening the construction period and cost of the excavation work itself, the wall construction and viscosity of the excavation mud filled in the excavation groove 15 are always maintained regardless of experience and skill level as in the past. It becomes possible to maintain the optimum state.
[0153]
In this embodiment, the sodium carbonate aqueous solution tank 3 is provided. However, if the dispersibility reduction at the time of cement mixing can be sufficiently suppressed by the drilling mud dispersant used in this embodiment, the sodium carbonate aqueous solution tank is used. 3 and the accompanying pump 8 and pipe 11 may be omitted. In such a configuration, the control target of the control device 19 is only the pump 6 and the pump 10.
[0154]
Further, in this embodiment, it is assumed that the mud film forming agent for drilling mud and the dispersant for drilling mud are used in combination, and these are stored in the chemical tank 2, but these chemicals are all constant. Since it has dispersibility and wall-forming property, depending on the case, either one may be used alone. On the other hand, when using a mud film forming agent for drilling mud and a dispersing agent for drilling mud, they may be stored in the chemical tank 2 in a mixed state, but they should be stored in dedicated tanks. It doesn't matter. In this case, two types of drug tanks 2 are provided. 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 chemical tank 2 is a total of three types: a drilling mud dispersant, a drilling mud dispersant (SS-B), and a drilling mud dispersant (sodium carbonate only).
[0155]
In the present embodiment, the liquid mixture prepared in the mixing tank 5 is once stored in the intermediate storage tank 13. However, the intermediate storage tank 13 is omitted and the mixed liquid is directly put into the excavation groove 15. Needless to say. In such a case, the mixed liquid discharge pipe 14 may be directly connected to the mixing tank 5.
[0156]
Further, in this embodiment, the mixing tank 5 is provided on the assumption that the mud film forming agent for drilling mud and the dispersant for drilling mud are diluted and then introduced into the drilling groove 15. If there is no hindrance to the quality control of the drilling mud described above even if added directly to 15, the mixing tank 5 is omitted, and the pipe 7 connected to the chemical tank 2 and the fresh water tank 4 are connected. The pipe 11 may be directly communicated with the excavation groove 15. Even in such a case, the control operation to the pump 6 and the pump 10 by the control device 19 is the same as that in the above-described embodiment, and the description of the operation and effect is omitted here.
[0157]
Although not specifically mentioned in the present embodiment, the intermediate storage tank 13 may be replaced with a conventionally used recovery tank, that is, a tank for recovering and storing the excavated mud after the concrete replacement. Alternatively, any tank installed in the circulation path for earth and sand separation, such as a circulation tank or a muddy water storage tank, may be substituted.
[0158]
Further, in the present embodiment, the measurement tank 17 for temporarily storing the muddy water in the excavation groove 15 is provided, but this may be omitted, and the muddy water in the excavation groove 15 may be directly drawn out. It goes without saying that any tank installed in the circulation path for earth and sand separation, for example, a circulation tank, a muddy water storage tank or the like may be extracted.
[0159]
【Example】
Next, the mud film forming agent 41 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.
[0160]
First, as the unsaturated carboxylic acid and / or salt (a) thereof, sodium acrylate was used as described in the above-described embodiment, and this was polymerized to produce a single polymer 41.
[0161]
Table 4 shows the wall-forming property (ml), viscosity (concentration; 25% by mass) of the single polymer 41 when the weight average molecular weight Mw is changed, and the viscosity of the muddy water (mPa · s) when mixed with muddy water. It is a thing.
[0162]
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.
[0163]
However, the following columns are used.
Column: TSKgel α-3000 + TSKgel α-6000
[0164]
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.
[0165]
Further, the muddy water before the addition of the single polymer 41 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.
[0166]
[Table 4]

[0167]
In the same table, the blank is the case of only muddy water, the ones of Examples 1 ′ to 9 ′ are the single polymer 41, and the amount of filtrate is 5 ml or less, which is an index of wall-forming property. The cases described as Comparative Example 1 ′ to Comparative Example 3 ′ are cases in which the amount of drainage of the single polymer 41 exceeded 5 ml. For comparison with the prior art, the case of using CMC is also shown as Comparative Example 4 ′.
[0168]
Further, FIG. 6 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.
[0169]
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.
[0170]
The production process of the single polymer 41 will be specifically described in the case of Example 1 ′ described above. First, 440.7 parts of water was charged in a reaction vessel, and after nitrogen substitution, 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 at the same time 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.
[0171]
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 41 and the case where both were used together with the single polymer 41 were examined.
[0172]
The experimental results are shown in Table 5 and FIG.
[0173]
[Table 5]

[0174]
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.
[0175]
【The invention's effect】
As described above, according to the mud management system according to the present invention, the mud film forming agent for drilling mud, the dispersant for drilling mud, or the fresh water are all in a liquid state, which is different from conventional mud production materials such as bentonite. In addition, it does not require labor and time for kneading, and as a result, it is possible to carry out the mud making work and the work for inserting into the borehole almost simultaneously without causing a time lag.
[0176]
That is, the mud film forming agent for drilling mud and the dispersant for drilling mud used in the present invention are quickly and easily put into the drilling hole as necessary and peptized into the drilling hole. Since it is possible to obtain a new excavation mud together with the fine particles of the excavated soil, as a result, it is possible to quickly and easily produce the excavation mud according to the excavation depth.
[0177]
Assuming this situation, the level of the muddy water in the borehole is measured with a liquid level gauge, and the property of the muddy water in the borehole is measured with a mud measuring device. Since the discharge control means and the fresh water discharge control means are controlled by the control device to control the supply and stop of the chemicals and fresh water to the excavation holes, it is possible to automate the mud drilling work, and the excavation work itself The construction period can be shortened and the cost can be reduced, and the wall-forming property and viscosity of the drilling mud filled in the drilling hole are always maintained in the optimum state regardless of the experience and skill level as in the past. It becomes possible.
[0178]
[Brief description of the drawings]
FIG. 1 is a diagram showing a muddy water management system 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 a graph showing experimental results regarding the muddy water management system according to the present embodiment.
FIG. 4 is a graph showing experimental results for the muddy water management system according to the present embodiment.
FIG. 5 is a chemical structural formula showing a mud film forming agent for drilling mud used in the second embodiment.
FIG. 6 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. 7 is a graph showing alkali resistance of a dispersant for drilling mud used in the second embodiment.
[Explanation of symbols]
1 Muddy water management system
2 drug tank
4 Fresh water tank (fresh water supply means)
5 Mixing tank
15 Drilling groove (drilling hole)
16 Level gauge
18 Muddy water measuring device
19 Control device
21 Drilling mud film forming agent
22 Sodium methacrylate (unsaturated carboxylate (a))
23 Methoxypolyethylene glycol methacrylate (monoester (b))
41 Single polymer ((co) polymer (x ′))
42 Sodium acrylate (unsaturated carboxylate (a))

Claims (5)

A chemical tank storing a mud film forming agent for drilling mud having a predetermined dispersibility and wall-forming property by being combined with fine particles of drilling earth and sand, fresh water supply means capable of supplying fresh water, and the drilling A mud film forming agent for mud and the fresh water are mixed to produce a mixed liquid, and the mixed liquid is supplied to the excavation hole, and the discharge is provided on the discharge side of the chemical tank. Possible medicine discharge control means, fresh water discharge control means provided on the discharge side of the fresh water supply means and capable of controlling the discharge thereof, a liquid level gauge for measuring the level of muddy water in the borehole, and the excavation A muddy water measuring device that measures the properties of the muddy water in the hole, and a control device connected to the liquid level meter and the muddy water measuring device, and using the liquid level data from the liquid level meter To control the discharge control means for fresh water The amount of fresh water to be refilled in the borehole is supplied to the mixing tank so that the muddy liquid level is maintained within a predetermined level or allowable range, and from the muddy water measuring device. A muddy water management system configured to supply the mixing tank with an amount of the drug added into the excavation hole by controlling the discharge control means for the drug using muddy water state data . A chemical tank storing a mud film forming agent for drilling mud that is liquid and has a predetermined dispersibility and wall-forming property by being combined with fine particles of excavated earth and sand, fresh water supply means capable of supplying fresh water, and the chemical Drug discharge control means provided on the discharge side of the tank and capable of controlling discharge thereof, fresh water supply control means provided on the discharge side of the fresh water supply means and capable of controlling discharge thereof, and muddy water in the excavation hole A liquid level meter for measuring the liquid level, a muddy water measuring device for measuring the properties of the muddy water in the excavation hole, and a control device connected to the liquid level meter and the muddy water measuring device, Then, by controlling the fresh water discharge control means using the liquid level data from the liquid level gauge, an amount of fresh water to be replenished in the excavation hole is supplied to the excavation hole, and the muddy water level is set. Maintained within a given level or tolerance The amount of medicine added to the borehole is supplied to the drilling hole by controlling the discharge control means for the medicine using the muddy water state data from the mudwater measuring device. A muddy water management system characterized by the above configuration . The mud film forming agent for drilling mud is made 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 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) The mud management system according to claim 1 or 2 , wherein bentonite and CMC are made unnecessary as mud-making materials by setting the molecular weight to 5000 to 100,000 . The drilling mud for mud film forming agent, an unsaturated carboxylic acid and / or weight-average molecular weight Mw to a salt thereof (a) only the constituent units from 200000 to 3000000 (co) polymer (x ') only The muddy water management system according to claim 1 or 2, wherein bentonite and CMC are made unnecessary as a mud-making material .   A liquid drilling mud dispersant is stored in the chemical 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 muddy water management system according to any one of claims 1 to 4, wherein the muddy water management system is configured of at least one of sodium.

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