JP4057817B2

JP4057817B2 - Bicarbonate hardener used for silicate soil stabilization chemicals and ground stabilization method using the same

Info

Publication number: JP4057817B2
Application number: JP2002028504A
Authority: JP
Inventors: 雅中村; 健司澤田
Original assignee: Mitsubishi Chemical Corp; Mitsubishi Rayon Co Ltd
Current assignee: Mitsubishi Chemical Corp
Priority date: 2002-02-05
Filing date: 2002-02-05
Publication date: 2008-03-05
Anticipated expiration: 2022-02-05
Also published as: JP2003226874A

Description

【０００１】
【発明の属する技術分野】
本発明は珪酸塩系土質安定用薬液における重炭酸塩系硬化剤に関する。
【０００２】
【従来技術および問題点】
従来、軟弱地盤を強化したり漏水地盤を止水するために、種々の薬液を地盤内に注入し、地盤中でゲル化させる地盤安定化工法が知られているが、特にアルカリ珪酸塩水溶液を主剤液とし、これと硬化剤とを組み合わせた薬液からなる、いわゆる珪酸塩系土質安定用薬液は安価であり、他の土質安定用薬液と比較して公害を起こす恐れが小さい等の特徴があり現在広く実用化されている。
【０００３】
珪酸塩系土質安定用薬液は、硬化剤の使用量を適宜変化させ施工の目的や地盤の状況に応じ、所望のゲルタイムに調整され施工が行われている。これら珪酸塩系土質安定用薬液の硬化剤としては、従来種々の物質が提案されているが、危険性がなくて取扱いが容易なこと、その使用量を変えることで薬液のゲルタイムを数秒から数分の範囲いわゆる瞬結型から緩結型まで幅広く調整出来る事などの点から、重炭酸塩からなる硬化剤、すなわち重炭酸塩系硬化剤が広く用いられている。
【０００４】
従来の重炭酸塩系硬化剤は長期間貯蔵した場合、硬化剤が固結し、硬化剤を水に溶解させ硬化剤液を調製している時に溶解槽の撹拌羽を破壊するなどの問題点があった。また、特にゲルタイムを早くするためにアルカリ珪酸塩に対する硬化剤重量比を高めた場合、硬化剤液を調製する際、硬化剤を水に溶解させるのに長時間を要し(溶解時間が長い)、施工が長引くなどの作業上の問題点もあった。さらに、アルカリ珪酸塩に対する硬化剤の使用量を変化させ、薬液のゲルタイムを10数秒から数分の範囲のいわゆる緩結に調整した場合やゲルタイム10秒以内のいわゆる瞬結に調整した場合にも、安定化処理した地盤の強度が低く,処理した地盤を切削したときに該地盤が崩壊したり亀裂を生じる等の問題点があった。
【０００５】
ところで、出願人は特公昭56−54034号公報で重炭酸塩系硬化剤として重炭酸ナトリウムおよび／または重炭酸カリウムと、該重炭酸塩に対し10〜40％の塩化カリウムとを組み合わせることにより、ゲルタイムが数秒ないし１０数秒の短時間でゲル化させる瞬結工法
の場面(土質安定用薬液と土壌との混合が困難となる)であっても、十分な強度をあたえる地盤の安定化工法を提案している。
【０００６】
この特公昭56−54034号公報記載の重炭酸塩系硬化剤を用いた地盤安定化法は、強度の改良に着眼したものであるが、固結や溶解性はいまだ、改良されたものとはなっておらず、改善が望まれていた。また、強度に関しては従来の重炭酸塩系硬化剤を用いた場合に比較して著しい改善がなされていたが、超軟弱地盤のようなさらに強度を必要とする場面においては、いまだ十分とは言えず、更なる改善が望まれていた。
【０００７】
【発明が解決しようとする課題】
本発明の目的は、珪酸塩系土質安定用薬液における重炭酸塩からなる硬化剤、すなわち重炭酸塩系硬化剤であって、長期間貯蔵しても固結を起こさず、かつ水への溶解性が良く、形成する硬化体の強度の発現が良好である重炭酸塩系硬化剤およびこれを用いた地盤安定化工法を提供することにある。
【０００８】
【課題を解決するための手段】
本発明者らは、前記問題点を改善し課題を解決すべく鋭意検討した結果、珪酸塩系土質安定用薬液に用いる重炭酸塩系硬化剤が下記ａ成分およびｂ成分と、下記ｃ成分および／またはｄ成分とを含む重炭酸塩系硬化剤とすることにより意外にも従来の重炭酸塩系硬化剤の有する問題点を解決出来ることを見出した。
【０００９】
ａ成分：重炭酸アルカリ金属塩
ｂ成分：アルカリ金属の塩化物
ｃ成分：ナフタレンスルホン酸系化合物、リグニンスルホン酸系化合物、オキシポリカルボン酸系化合物及びメラミンスルホン酸系化合物よりなる群から選ばれた少なくとも一種。
ｄ成分：炭酸アルカリ金属塩
【００１０】
【発明の実施の形態】
以下、本発明の詳細を説明する
本発明の硬化剤は、これらａ成分およびｂ成分と、下記ｃ成分および／またはｄ成分とを含んでなる。
【００１１】
本発明の硬化剤中のａ成分の重炭酸アルカリ金属塩はMHCO₃（MはLi、Na、K等のアルカリ金属元素を示す）の化学式で表現される化合物であり、試薬、工業品等、一般に市販されているものを用いることが出来る。ａ成分の例として重炭酸リチウム、重炭酸カリウム、重炭酸ナトリウム等があげられ、これらを単独または混合して用いることが出来るが、一軸圧縮強度の面で、好ましくは重炭酸カリウムと重炭酸ナトリウムの混合物でその重炭酸カリウムの量比が重炭酸ナトリウム100質量部あたり15〜600質量部で混合されたものが良い。
【００１２】
本発明の硬化剤中のｂ成分はMCl(MはLi、Na、K等ののアルカリ金属元素を示す)の化学式で表現される化合物であり、試薬、工業品等、一般に市販されているものを用いることが出来る。ｂ成分の例として塩化カリウム、塩化ナトリウム、塩化リチウム等があげられ、これらを単独または混合して用いることができるが、一軸圧縮強度の面で、好ましくは塩化カリウムを単独で用いるのが良い。
【００１３】
ｂ成分の質量比は一軸圧縮強度の面でａ成分100質量部あたり10質量部〜160質量部が好ましく、さらに好ましくは20質量部〜150質量部である。
【００１４】
本発明の硬化剤中のｃ成分はナフタレンスルホン酸系化合物、リグニンスルホン酸系化合物、オキシポリカルボン酸系化合物及びメラミンスルホン酸系化合物よりなる群から選ばれた一種である。
【００１５】
ナフタレンスルホン酸系化合物はナフタレンスルホン酸やアルキルアリルスルホン酸のアルカリ(土類)金属塩、またはこれらのホルマリン縮合物などの各種誘導体で、市販品では、例えばマイティ100(花王(株)社製)をあげることが出来る。リグニンスルホン酸系化合物はリグニンスルホン酸のアルカリ(土類)金属塩、またはこれらのホルマリン縮合物などの各種誘導体で、市販品では例えば、サンフローＲ(サンフロー(株)社製)をあげることが出来る。ポリカルボン酸系化合物はカルボキシル基を有する化合物のアルカリ(土類)金属塩の付加または縮合重合物などの各種誘導体で、例えば市販品のパリック＃１(エフ・ピー・ケイ(株)製))を35℃で質量変化5％未満になるまで乾燥させたもの等を用いることが出来る。メラミンスルホン酸系化合物はメラミンスルホン酸のアルカリ(土類)金属塩、またはこれらのホルマリン縮合物などの各種誘導体で、市販品では例えば、SMF-PD(日産化学工業(株)製)を挙げることが出来る。
【００１６】
これらｃ成分はいずれも粉末状のものが好ましい。液状のものを用いると固結の原因となる場合がある。
【００１７】
ｃ成分の質量比は固結、溶解性、一軸圧縮強度の面で（ａ成分＋ｂ成分）100質量部あたり0.02〜4質量部が好ましく、さらに好ましくは0.04質量部〜3質量部である。
【００１８】
本発明の硬化剤中のｄ成分はM₂CO₃(MはLi、Na、K等のアルカリ金属元素を示す)の化学式で表現される化合物であり、試薬、工業品等、一般に市販されているものを用いることが出来る。
【００１９】
ｄ成分の例として炭酸リチウム、炭酸ナトリウム、炭酸カリウム等があげられ、これらを単独または混合して用いることが出来る。
【００２０】
ｄ成分の質量比は固結、溶解性、一軸圧縮強度の面で（ａ成分＋ｂ成分）100質量部あたり0.02質量部〜14質量部が好ましく、さらに好ましくは0.04質量部〜13質量部である。
【００２１】
尚、ｃ成分とｄ成分は溶解性や固結の面で上記範囲内で組み合わせて用いるのが好ましい。
【００２２】
本発明の硬化剤は、主剤のアルカリ珪酸塩と組み合わせて珪酸塩系土質安定用薬液として使用される。その主剤のアルカリ珪酸塩としては、従来から珪酸塩系土質安定用薬液に用いられている珪酸ソーダやSiO₂/Na₂O（モル比）が４〜６の範囲であるシリカゾル等を用いることができる。珪酸ソーダの例としては、日本工業規格（JIS K1408）に規定されている１〜３号珪酸ソーダ、商品名「ニトロック」（（株）菱晃社製）等があげられる。
【００２３】
施工に際しては、前もって硬化剤を水に溶解した硬化剤液（以下、Ｂ液という）と、主剤のアルカリ珪酸塩を水で希釈した主剤液（以下、Ａ液という）を調製しておき、これらを目的の強度やゲルタイムが得られるように適宜の比率で混合し、地盤に注入して硬化させ地盤を安定化するのが一般的である。
【００２４】
主剤と硬化剤の比、Ａ液やＢ液の濃度、あるいはＡ液とＢ液の比は特に限定されるものではなく、目的の強度や施工方法に応じて適宜設定することが出来る。
【００２５】
薬液中の主剤量を多くすると固結強度を高く、一方、主剤量を少なくすると固結強度を低くすることが出来る。また、硬化剤使用量を多くすると薬液のゲルタイムを短く調整することが出来、一方少なくすると薬液のゲルタイムを長く調整することが出来る。
【００２６】
例えば、Ａ液とＢ液とを等容量ずつ混合しながら地盤中に注入する代表的な施工法で、主剤のアルカリ珪酸塩としてJIS3号水ガラスを用いた場合は、通常、薬液400リットル中、JIS3号水ガラス60〜120リットル、本発明の硬化剤を通常10.0kg〜35.0kgの範囲となるように調製し地盤に注入する
本発明の硬化剤を用いた薬液を地盤内の注入する方法は、特に限定されるものではなく、公知の単菅式、二重菅式、多重菅式などの各種注入菅に用いる事ができる。またＡ液とＢ液とを予め混合して注入菅に導く方法、Ａ液とＢ液とを注入間の基部に設けた混合部−例えば、Ｙ字菅において混合して注入管に導く方法、あるいは、Ａ液とＢ液とをそれぞれ独立に注入菅に導いて注入菅内で混合する方法，あるいは、Ａ液とＢ液とをそれぞれ独立に注入菅に導いて、注入菅から地盤内に注入しながら地盤内において合流・混合させる等適宜の方法を薬液のゲルタイムや施工性に応じて採用することが出来る。
【００２７】
【実施例】
次に、実施例および比較例によって、本発明を具体的に説明するが、本発明はこれら実施例に限定されるものではない。
【００２８】
（硬化剤の調製）
表１に示した量比でａ〜ｄ成分を混合し、硬化剤を調製した。混合には、ナウターミキサーを用い、ａ、ｂ、ｃ、ｄ成分の順で添加し３０分間混合した。なお、ａ成分の重炭酸アルカリ金属塩、ｂ成分のアルカリ金属塩の塩化物およびｄ成分の炭酸アルカリ金属塩はいずれも試薬１級を用い、ｃ成分には以下の物質を用いた。また、ａ〜ｄ成分はいずれも２４メッシュのふるいを通過させた物を用いた。
【００２９】
・粉末ナフタレンスルホン酸系化合物：マイティ100(花王(株)社製)
・粉末リグニンスルホン酸系化合物：サンフローＲ(サンフロー(株)社製)
・粉末オキシポリカルボン酸系化合物：パリック＃１(エフ・ピー・ケイ(株))を35℃で重量変化0.1％未満になるまで乾燥させたもの。
・粉末メラミンスルホン酸系化合物：SMF-PD(日産化学工業(株)製)
・脂肪酸アルキルエステル：パステルM-180(ライオン(株)製)
（固結性評価）
表１の硬化剤450gを15cm×18cmのポリエチレン袋（0.5mmφ×6ヶのピンホールをつけたもの）に入れ封をした。これを試験体とし0.02N/mm²荷重のもと35℃、R.H.65%の恒温恒湿室内で一年間貯蔵した。
【００３０】
しかる後、試験体を12メッシュのふるい上にあけ、ふるい上に残った重量Ａ(g)とふるいを通過した重量をＢ(g)測定し、最後に下式より固結率を算出した。結果を表１に示した。
固結率（％）＝Ａ／（Ａ＋Ｂ）×100
【００３１】
（水への溶解性評価）
表１の硬化剤20kgを５℃の環境下、ドラム缶内に入れ、これに硬化剤液が200リットルとなるように５℃の水を加え、ミキサー（パワーミックスPM220B東芝(株)製）を用いて攪拌し硬化剤が完全に溶解するまでの時間を測定した。結果を表１に示した。
【００３２】
（硬化体の一軸圧縮強度測定）
下記のようにしてＡ液とＢ液を調製した。
Ａ液・・・JIS３号珪酸ソーダ80リットルに水120リットルを加えてＡ液を調製した。
Ｂ液・・・表１の硬化剤を表２、表３に示した量計り取り容量200リットルとなるように水を加え、硬化剤を完全に溶解させＢ液とした。
【００３３】
Ａ液、Ｂ液各50mlを20℃で混合した。この混合液を円柱の型枠（径５cm×高さ10cm）内に流し込み、硬化体を作成した。得られた硬化体の材令１日の一軸圧縮強度値を圧縮試験機(テンシロン)で測定した。ゲルタイム、硬化体一軸圧縮強度の測定結果を表２、表３に示した。
【００３４】
(結果)
比較例１〜３は硬化剤がａ成分のみの場合である。この場合、硬化体の一軸圧縮強度、硬化剤の固結性および水への溶解性のいずれも良好な結果は得られなかった。
【００３５】
比較例４〜９は硬化剤がａ成分とｂ成分からなる場合である。この場合、ａ成分のみからなる比較例１〜３と比較し一軸圧縮強度に関して良好な結果となるがいまだ十分でなかった。また、固結性および水への溶解性に関しては、いずれも良好な結果は得られなかった。
【００３６】
これに対して、ａ成分およびｂ成分とｃ成分および／またはｄ成分からなる硬化剤を用いた実施例１〜３１では、一軸圧縮強度、固結性、および水への溶解性いずれも良好な結果が得られ、本発明の目的を達成することが出来た。
【００３７】
【表１】

【表２】

【表３】

【００３８】
【発明の効果】
本発明の珪酸塩系土質安定用薬液の重炭酸塩系硬化剤によれば従来の硬化剤組成の組み合わせでは得られなかった性能、すなわち、長期間貯蔵しても固結を起こしにくく、かつ水への溶解性が良く、形成する硬化体の強度の発現を良好でより安全、確実に地盤を安定化出来る。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a bicarbonate-based curing agent in a silicate-based soil stabilization chemical.
[0002]
[Prior art and problems]
Conventionally, in order to strengthen the soft ground or stop the leaked ground, there are known ground stabilization methods in which various chemicals are injected into the ground and gelled in the ground. The so-called silicate-based soil stabilization chemical solution, which consists of a chemical solution that combines the main agent solution and the curing agent, is inexpensive and has the characteristics that it is less likely to cause pollution compared to other soil stabilization chemical solutions. Currently in wide use.
[0003]
The silicate-based soil stabilization chemical solution is adjusted to a desired gel time according to the purpose of construction and the ground condition by appropriately changing the amount of the curing agent used. Various materials have been proposed as curing agents for these silicate-based soil stabilization chemicals, but they are easy to handle without danger, and the gel time of chemicals can be reduced from a few seconds by changing the amount used. From the point that it can be widely adjusted from a so-called instantaneous setting type to a slow setting type, a curing agent made of bicarbonate, that is, a bicarbonate-based curing agent is widely used.
[0004]
When the conventional bicarbonate-based curing agent is stored for a long period of time, the curing agent solidifies, and when the curing agent solution is prepared by dissolving the curing agent in water, the stirring blades in the dissolution tank are destroyed. was there. Also, especially when the weight ratio of the curing agent to the alkali silicate is increased in order to increase the gel time, it takes a long time to dissolve the curing agent in water when preparing the curing agent liquid (long dissolution time). There were also problems in work such as prolonged construction. Furthermore, even when the amount of curing agent used for alkali silicate is changed and the gel time of the chemical solution is adjusted to the so-called slow setting in the range of several tens of seconds to several minutes, or when the gel time is adjusted to the so-called instantaneous setting within 10 seconds, The strength of the stabilized ground was low, and when the treated ground was cut, the ground collapsed or cracked.
[0005]
Meanwhile, the applicant of sodium bicarbonate and / or potassium bicarbonate as a bicarbonate salt curing agent in Japanese Patent Sho JP publicly 56-54034, by combining 10 to 40 percent of potassium chloride to the heavy carbonate Even in the scene of the instantaneous setting method in which the gel time is gelled in a short time of several seconds to several tens of seconds (mixing of the chemical solution for soil stabilization and soil becomes difficult), the ground stabilization method that provides sufficient strength is suggesting.
[0006]
Soil stabilization method using bicarbonate-based curing agent of the Japanese public Sho 56-54034 discloses described, as it is obtained by focusing on improvement of strength, are still, to an improved consolidated and solubility There was no need for improvement. In addition, the strength has been remarkably improved as compared with the case of using a conventional bicarbonate-based curing agent, but it is still sufficient in a scene that requires further strength such as an ultra-soft ground. However, further improvements were desired.
[0007]
[Problems to be solved by the invention]
The object of the present invention is a curing agent comprising bicarbonate in a silicate-based soil stabilization chemical solution, that is, a bicarbonate-based curing agent, which does not cause solidification even when stored for a long period of time and dissolves in water. An object of the present invention is to provide a bicarbonate-based curing agent having good properties and good strength expression of a cured body to be formed, and a ground stabilization method using the same.
[0008]
[Means for Solving the Problems]
As a result of intensive studies to improve the above problems and solve the problems, the present inventors have found that the bicarbonate-based curing agent used in the silicate-based soil stabilization chemical solution has the following components a and b, and c and It has been found that by using a bicarbonate-based curing agent containing d / component, it is possible to solve the problems of conventional bicarbonate-based curing agents.
[0009]
Component a: alkali metal bicarbonate salt b component: alkali metal chloride c component: selected from the group consisting of naphthalene sulfonic acid compounds, lignin sulfonic acid compounds, oxypolycarboxylic acid compounds and melamine sulfonic acid compounds At least one kind.
d component: alkali metal carbonate
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the curing agent of the present invention for explaining the details of the present invention comprises these a component and b component and the following c component and / or d component.
[0011]
The alkali metal bicarbonate of component a in the curing agent of the present invention is a compound represented by a chemical formula of MHCO ₃ (M represents an alkali metal element such as Li, Na, K, etc.). A commercially available product can be used. Examples of the component a include lithium bicarbonate, potassium bicarbonate, sodium bicarbonate, and the like. These can be used alone or in combination, but in terms of uniaxial compressive strength, preferably potassium bicarbonate and sodium bicarbonate. A mixture in which the amount ratio of potassium bicarbonate is 15 to 600 parts by mass per 100 parts by mass of sodium bicarbonate is preferable.
[0012]
Component b in the curing agent of the present invention is a compound represented by the chemical formula of MCl (M represents an alkali metal element such as Li, Na, K, etc.), and is generally commercially available as a reagent, industrial product, etc. Can be used. Examples of the component b include potassium chloride, sodium chloride, lithium chloride and the like, and these can be used alone or in combination, but potassium chloride is preferably used alone in terms of uniaxial compressive strength.
[0013]
The mass ratio of component b is preferably 10 to 160 parts by mass, more preferably 20 to 150 parts by mass, per 100 parts by mass of component a in terms of uniaxial compressive strength.
[0014]
The component c in the curing agent of the present invention is a kind selected from the group consisting of naphthalene sulfonic acid compounds, lignin sulfonic acid compounds, oxypolycarboxylic acid compounds and melamine sulfonic acid compounds.
[0015]
Naphthalene sulfonic acid compounds are various derivatives such as alkali (earth) metal salts of naphthalene sulfonic acid and alkylallyl sulfonic acid, or formalin condensates thereof, and commercially available products such as Mighty 100 (manufactured by Kao Corporation) Can be given. Lignin sulfonic acid compounds are various derivatives such as alkali (earth) metal salts of lignin sulfonic acid, or their formalin condensates. Examples of commercially available products include Sun Flow R (manufactured by Sun Flow Co., Ltd.). I can do it. Polycarboxylic acid compounds are various derivatives such as addition of alkali (earth) metal salts of compounds having a carboxyl group or condensation polymerization products, for example, commercially available Paric # 1 (manufactured by FP K.K.)) Can be used at 35 ° C. until the mass change is less than 5%. Melamine sulfonic acid compounds are various derivatives such as alkali (earth) metal salts of melamine sulfonic acid or their formalin condensates, and examples of commercially available products include SMF-PD (manufactured by Nissan Chemical Industries, Ltd.). I can do it.
[0016]
These c components are preferably powdery. If liquid material is used, it may cause caking.
[0017]
The mass ratio of component c is preferably 0.02 to 4 parts by mass, more preferably 0.04 to 3 parts by mass per 100 parts by mass (component a + component b) in terms of consolidation, solubility, and uniaxial compressive strength.
[0018]
The d component in the curing agent of the present invention is a compound represented by a chemical formula of M ₂ CO ₃ (M represents an alkali metal element such as Li, Na, K, etc.) and is generally commercially available as a reagent, an industrial product, etc. Can be used.
[0019]
Examples of the d component include lithium carbonate, sodium carbonate, potassium carbonate and the like, and these can be used alone or in combination.
[0020]
The mass ratio of d component is preferably 0.02 to 14 parts by mass, more preferably 0.04 to 13 parts by mass per 100 parts by mass (component a + component b) in terms of consolidation, solubility, and uniaxial compressive strength. .
[0021]
The c component and the d component are preferably used in combination within the above ranges in terms of solubility and consolidation.
[0022]
The curing agent of the present invention is used as a silicate-based soil stabilization chemical solution in combination with the base alkali silicate. As the alkali silicate as the main agent, sodium silicate or SiO ₂ / Na ₂ O (molar ratio) that is conventionally used for a silicate-based soil stabilization chemical solution or a silica sol having a molar ratio of 4 to 6 is used. it can. Examples of sodium silicate include Nos. 1 to 3 silicates stipulated in Japanese Industrial Standards (JIS K1408), trade name “Nitroc” (manufactured by Ryokan Co., Ltd.), and the like.
[0023]
At the time of construction, a hardener solution in which a hardener is dissolved in water (hereinafter referred to as B liquid) and a main agent liquid in which the base alkali silicate is diluted with water (hereinafter referred to as A liquid) are prepared in advance. Is generally mixed at an appropriate ratio so that the desired strength and gel time can be obtained, and then injected into the ground and hardened to stabilize the ground.
[0024]
The ratio of the main agent and the curing agent, the concentration of the A liquid and the B liquid, or the ratio of the A liquid and the B liquid is not particularly limited, and can be appropriately set according to the target strength and construction method.
[0025]
Increasing the amount of the main agent in the chemical solution increases the consolidation strength, while decreasing the amount of the main agent decreases the consolidation strength. Further, when the amount of the curing agent used is increased, the gel time of the chemical liquid can be adjusted to be short, while when it is decreased, the gel time of the chemical liquid can be adjusted to be long.
[0026]
For example, in a typical construction method in which liquid A and liquid B are mixed in equal volumes and injected into the ground, when JIS3 water glass is used as the base alkali silicate, JIS3 water glass 60-120 liters, the curing agent of the present invention is usually prepared in the range of 10.0kg-35.0kg and injected into the ground The method of injecting the chemical solution using the curing agent of the present invention into the ground is However, it is not particularly limited, and can be used for various types of injection rods such as a known single rod type, double rod type, and multiple rod type. Also, a method in which A liquid and B liquid are mixed in advance and led to an injection tank, a mixing section provided at the base between injections of A liquid and B liquid, for example, a method in which Y liquid is mixed and guided to an injection pipe, Alternatively, the A liquid and the B liquid are each led to the pouring basin independently and mixed in the pouring basin, or the A liquid and the B liquid are each independently guided to the pouring basin and injected from the pouring basin into the ground. However, an appropriate method such as merging and mixing in the ground can be employed depending on the gel time and workability of the chemical solution.
[0027]
【Example】
Next, although an example and a comparative example explain the present invention concretely, the present invention is not limited to these examples.
[0028]
(Preparation of curing agent)
Components a to d were mixed at a quantitative ratio shown in Table 1 to prepare a curing agent. For mixing, a Nauta mixer was used, and components a, b, c and d were added in this order and mixed for 30 minutes. The alkali metal bicarbonate salt of the component a, the chloride of the alkali metal salt of the component b and the alkali metal carbonate salt of the component d all used the first grade reagent, and the following substances were used for the component c. In addition, all the components a to d were passed through a 24-mesh sieve.
[0029]
・ Powder naphthalene sulfonic acid compound: Mighty 100 (manufactured by Kao Corporation)
・ Powdered lignin sulfonic acid compound: Sunflow R (manufactured by Sunflow Co., Ltd.)
・ Powdered oxypolycarboxylic acid compound: Paric # 1 (FPK Corporation) dried at 35 ° C. until the weight change is less than 0.1%.
・ Powdered melamine sulfonic acid compound: SMF-PD (manufactured by Nissan Chemical Industries, Ltd.)
・ Fatty acid alkyl ester: Pastel M-180 (manufactured by Lion Corporation)
(Consolidation evaluation)
450 g of the curing agent shown in Table 1 was placed in a 15 cm × 18 cm polyethylene bag (with 0.5 mmφ × 6 pinholes) and sealed. This was used as a test specimen and stored for one year in a constant temperature and humidity room at 35 ° C. and RH 65% under a load of 0.02 N / mm ² .
[0030]
Thereafter, the specimen was opened on a 12-mesh sieve, the weight A (g) remaining on the sieve and the weight passing through the sieve were measured B (g), and finally the consolidation rate was calculated from the following formula. The results are shown in Table 1.
Consolidation rate (%) = A / (A + B) × 100
[0031]
(Evaluation of solubility in water)
20kg of the curing agent shown in Table 1 is placed in a drum can in an environment of 5 ° C. Add 5 ° C water so that the curing agent solution becomes 200 liters, and use a mixer (Powermix PM220B manufactured by Toshiba Corporation). And the time until the curing agent was completely dissolved was measured. The results are shown in Table 1.
[0032]
(Measurement of uniaxial compressive strength of cured product)
A liquid and B liquid were prepared as follows.
Liquid A: Liquid A was prepared by adding 120 liters of water to 80 liters of JIS 3 sodium silicate.
Liquid B: The curing agent shown in Table 1 was added with water so that the measuring capacity shown in Tables 2 and 3 was 200 liters, and the curing agent was completely dissolved to obtain Liquid B.
[0033]
50 ml each of liquid A and liquid B were mixed at 20 ° C. This mixed liquid was poured into a cylindrical mold (diameter 5 cm × height 10 cm) to prepare a cured body. The uniaxial compressive strength value of the obtained cured product on the material day was measured with a compression tester (Tensilon). Tables 2 and 3 show the measurement results of gel time and uniaxial compressive strength of the cured body.
[0034]
(result)
Comparative Examples 1 to 3 are cases where the curing agent is only the component a. In this case, the uniaxial compressive strength of the cured product, the caking property of the curing agent, and the solubility in water were not satisfactory.
[0035]
Comparative Examples 4 to 9 are cases where the curing agent is composed of a component and b component. In this case, compared with Comparative Examples 1 to 3 consisting only of the component a, the uniaxial compressive strength was good, but it was not sufficient. In addition, as for the caking property and the solubility in water, good results were not obtained.
[0036]
On the other hand, in Examples 1-31 using the hardening | curing agent which consists of a component, b component, c component, and / or d component, uniaxial compressive strength, caking property, and the solubility to water are all favorable. The result was obtained and the object of the present invention could be achieved.
[0037]
[Table 1]

[Table 2]

[Table 3]

[0038]
【The invention's effect】
According to the bicarbonate-based curing agent of the silicate-based soil stabilization chemical solution of the present invention, performance that was not obtained by a combination of conventional curing agent compositions, that is, hard to cause consolidation even after long-term storage, and water Solubility is good, the strength of the cured body to be formed is good, and the ground can be stabilized more safely and reliably.

Claims

A bicarbonate-based curing agent used for a silicate-based soil stabilization chemical solution, wherein the curing agent includes the following a component and b component and the following c component and / or d component.
Component a: alkali metal bicarbonate salt b component: alkali metal chloride c component: selected from the group consisting of naphthalene sulfonic acid compounds, lignin sulfonic acid compounds, oxypolycarboxylic acid compounds and melamine sulfonic acid compounds At least one kind.
d component: alkali metal carbonate

The bicarbonate-based curing agent according to claim 1, wherein the amount ratio of the c component is in the range of 0.02 to 4 parts by mass of the c component per 100 parts by mass in total of the a component and the b component.

The bicarbonate-based curing agent according to claim 1 or 2, wherein the amount ratio of the d component is in the range of 0.02 to 14 parts by mass of the d component per 100 parts by mass of the total of the a component and the b component.

The bicarbonate type hardening | curing agent in any one of Claims 1 thru | or 3 whose quantity ratio of b component is 10-160 mass parts of b component per 100 mass parts of a component.

The bicarbonate-based curing agent according to any one of claims 1 to 4, comprising a component, b component, c component, and d component.

The bicarbonate system according to any one of claims 1 to 5, wherein the alkali bicarbonate of component a comprises potassium bicarbonate and sodium bicarbonate, and potassium bicarbonate is 15 to 600 parts by mass per 100 parts by mass of sodium bicarbonate. Curing agent.

A ground stabilization method using a silicate-based soil stabilization chemical prepared with the bicarbonate-based curing agent according to any one of claims 1 to 6.