JP2005220739A - Ground improvement method - Google Patents
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Abstract
Description
本発明は、地盤改良方法に関するものである。更に詳しく述べるならば、本発明は、地盤改良に用いられるセメント組成物の地盤改良性能を著しく向上させる地盤改良セメント用添加剤を用いる地盤改良方法に関するものである。 The present invention relates to a ground improvement method. More specifically, the present invention relates to a ground improvement method using an additive for ground improvement cement which remarkably improves the ground improvement performance of a cement composition used for ground improvement.
一般に、セメントスラリーと改良対象土を混合した混合土の特性として、なるべく粘性が低く、削孔する際のスライムの排出が容易になるような混合土が望まれる。しかし混合土に粘性土が多く含まれていると、混合土の粘度が高くなり、スライムの排出が困難になる。これは、混合土中の土粒子とセメント粒子が凝集して、流動性を失うためである。 In general, as a characteristic of the mixed soil obtained by mixing the cement slurry and the soil to be improved, a mixed soil having a viscosity as low as possible and facilitating the discharge of slime when drilling is desired. However, if the mixed soil contains a lot of viscous soil, the viscosity of the mixed soil increases and it becomes difficult to discharge slime. This is because soil particles and cement particles in the mixed soil aggregate and lose fluidity.
従来、この対策として、加水する方法と、混合土中の土粒子とセメント粒子の凝集を抑える（分散）方法がある。しかし、加水する方法では、硬化後の強度低下の要因になり、さらに、スライム量が多くなりすぎると、経済的な悪化の要因となる。混合土中の土粒子とセメント粒子の凝集を抑える（分散）方法では、スライムの粘性を低下させる目的のために、地盤改良用セメント組成物中に、ナフタレンスルホン酸塩ホルマリン縮合物、又はメラミンスルホン酸塩ホルマリン縮合物を添加し、これをセメント粒子及び土粒子に吸着させることにより、電気的反発力により土壌の粒子が互いに反発し、スライムの粘性を低下させることが可能であることが知られている。グラウト工法などの地盤改良材に使用される添加剤としてポリアクリル酸が提案されている（特許文献１：特許第３２５３２８２号）。 Conventionally, as countermeasures, there are a method of adding water and a method of suppressing (dispersing) aggregation of soil particles and cement particles in the mixed soil. However, the method of adding water causes a decrease in strength after curing, and if the amount of slime is excessive, it causes an economic deterioration. In the method of suppressing aggregation (dispersion) of soil particles and cement particles in the mixed soil, naphthalene sulfonate formalin condensate or melamine sulfone is included in the ground improvement cement composition for the purpose of reducing the viscosity of the slime. It is known that by adding salt formalin condensate and adsorbing it to cement particles and soil particles, the soil particles repel each other due to the electric repulsive force, and the slime viscosity can be reduced. ing. Polyacrylic acid has been proposed as an additive used for ground improvement materials such as the grout method (Patent Document 1: Japanese Patent No. 3253282).
さらに、地盤改良用セメント組成物中に重炭酸塩を添加することが知られている（特許文献２：特開平７−２０６４９５、特許文献３：特開平１０−２１２４８２）。 Furthermore, it is known to add a bicarbonate to the ground improvement cement composition (Patent Document 2: JP-A-7-206495, Patent Document 3: JP-A-10-212482).
また分散剤としては、ナフタレンスルホン酸やメラミンスルホン酸のホルマリン縮合物（特許文献４：特開昭６１−１４６７４７、特許文献５：特開平６−１２７９９３）では、スライムの粘性低下効果が充分ではなく、分散補助剤（ビルダー）として用いられる、炭酸塩及び硫酸塩（特許文献２：特開平７−２０６４９５、特許文献３：特開平１０−２１２４８２）には多価金属イオンの除去効果がなく、またリン酸塩は特定の化合物以外その効果は得られない。 As a dispersant, the formalin condensate of naphthalene sulfonic acid or melamine sulfonic acid (Patent Document 4: Japanese Patent Laid-Open No. 61-146747, Patent Document 5: Japanese Patent Laid-Open No. 6-127993) is not sufficient in reducing the viscosity of slime. Carbonate and sulfate (Patent Document 2: JP-A-7-206495, Patent Document 3: JP-A-10-212482) used as dispersion aids (builders) have no effect of removing polyvalent metal ions. Phosphates are not effective except for specific compounds.
また上記と類似の添加剤を使用した水硬性組成物も提案されているが、それに適用される工法が異なり、或は、使用される目的が異なるものである。その一例として、水溶性高分子（ポリアクリル酸）と重炭酸塩とを含む水硬性組成物（特許文献６：特許２６６８５９８号）は、高炉スラグをベースに、アルカリの存在下で高強度複合材料を得るものであって、本発明の地盤改良セメント組成物用添加剤とは異なるものである。
高性能減水剤と重炭酸塩を含むセメント混和材（特許文献７：特開平１１−７１１４７、特許文献８：特開平１１−１１６３０６）は、高強度コンクリート（モルタル）を目的とするセメント組成物であり、また高性能減水剤は、ナフタレンスルホン酸、メラミンスルホン酸などのホルマリン縮合物であり、さらに重炭酸塩は、凝結促進剤または急結剤として使用されている。コンクリートのワーカビリティ改良方法（特許文献９：特公平１−５２３４２）としても使用されているが、地盤改良に用いられることについては全く教示も示唆もされていない。（実施例１参照）
A hydraulic composition using an additive similar to the above has also been proposed, but the construction method applied thereto is different or the purpose of use is different. As an example, a hydraulic composition (Patent Document 6: Japanese Patent No. 2668598) containing a water-soluble polymer (polyacrylic acid) and bicarbonate is a high-strength composite material in the presence of alkali based on blast furnace slag. This is different from the additive for ground improvement cement composition of the present invention.
A cement admixture containing a high-performance water reducing agent and bicarbonate (Patent Document 7: JP-A-11-711147, Patent Document 8: JP-A-11-116306) is a cement composition intended for high-strength concrete (mortar). In addition, high-performance water reducing agents are formalin condensates such as naphthalene sulfonic acid and melamine sulfonic acid, and bicarbonate is used as a setting accelerator or rapid setting agent. Although it is also used as a method for improving the workability of concrete (Patent Document 9: Japanese Patent Publication No. 1-52342), there is no teaching or suggestion that it is used for ground improvement. (See Example 1)
しかし特許文献１に記載の添加剤は、内陸部などの粘性土（ミネラル分が少ない）に用いると、顕著な粘性低下の効果が得られるが、海成粘土などのようにミネラル分（特に多価金属イオン）を含む粘性土に用いると、多価金属イオンが、電気二重層を圧縮し、分散メカニズムを阻害するために充分な粘性低下の効果が得られないという問題点がある。
特許文献２及び３に記載の方法によればその土のミネラル分を除去することによる凝集防止は可能であるが、海成粘土以外の、ミネラル分が少ない粘性土の分散（粘性低下）には、充分な効果がないことが判明している。
本発明は、地盤改良セメント組成物を改良すべき地盤に打設したとき、地盤改良セメント組成物の、この改良対象土中への拡散及び混合が迅速で、地盤改良セメント組成物の打設により地盤から排出されるべきスライムの排出が円滑に行われ、かつ排出されたスライムが海水中に流入したとき、その周辺海域の汚濁を防止乃至減少させることが可能な地盤改良方法を提供しようとするものである。
However, when the additive described in Patent Document 1 is used for clayey soil (low mineral content) such as inland areas, the effect of remarkable viscosity reduction can be obtained. When used in a viscous soil containing a valent metal ion), the polyvalent metal ion compresses the electric double layer, and there is a problem that a sufficient viscosity reduction effect cannot be obtained to inhibit the dispersion mechanism.
According to the methods described in Patent Documents 2 and 3, it is possible to prevent aggregation by removing the mineral content of the soil, but for the dispersion (viscosity reduction) of viscous soil with a small amount of mineral other than marine clay. It has been found that there is not enough effect.
In the present invention, when the ground improvement cement composition is placed on the ground to be improved, the ground improvement cement composition is rapidly diffused and mixed into the soil to be improved. An object of the present invention is to provide a ground improvement method capable of smoothly or smoothly reducing the slime to be discharged from the ground and preventing or reducing the pollution of the surrounding sea area when the discharged slime flows into the seawater. Is.
本発明の地盤改良方法は、少なくとも５０質量％以上のセメントを含むセメント系固化材と、このセメント系固化材１００質量部に対し、０．１〜２５質量部の、（イ）エチレン性不飽和モノカルボン酸及びエチレン性不飽和ジカルボン酸から選ばれた少なくとも１種の重合体及び共重合体及びそれらの水溶性塩の少なくとも１種を含む重合体成分と、及び（ロ）水溶性重炭酸塩の少なくとも１種を含む重炭酸塩成分とを含む添加剤とを含む、地盤改良セメント組成物とを、その質量の５０〜２００％の混練水に混合して地盤改良セメント組成物スラリーを調製し、この地盤改良セメント組成物スラリーを、改良すべき地盤中に、改良対象土の容積の０．１〜１．５倍の容積をもって打設・混合し、硬化させることを特徴とするものである。
本発明の地盤改良セメント組成物において、前記地盤改良セメント組成物スラリー中に、追加添加材料として、高炉スラグ、石灰石粉、フライアッシニ、シリカ微粉末、炭酸カルシウム及び石膏から選ばれた少なくとも１種を更に添加してもよい。
本発明の地盤改良方法は、前記地盤が、土粒子径７５μｍ以下の細粉分を５０質量％以上の含有率で含むか、又は５μｍ以下の土粒子径を有する粘土分を２０質量％以上の含有率で含み、前記地盤改良セメント組成物スラリーにおける混練水の質量Ｗの地盤改良セメント組成物の質量Ｃに対する質量比Ｗ／Ｃが１：０．５〜１：２である場合にも、著しく有効である。
本発明の地盤改良方法において、前記添加剤中の前記重合体成分（イ）と、前記重炭酸塩成分（ロ）との質量比が、１００：５００〜１００：５，０００であることが好ましい。
前記添加剤中の重合体成分（イ）が、アクリル酸、メタアクリル酸、マレイン酸、フマル酸、及びイタコン酸の重合体及び共重合体及びそれらのアルカリ金属塩、アンモニウム塩及び低級アルキルアンモニウム塩から選ばれた少なくとも１種を含むことが好ましい。
前記添加剤中の重合体成分（イ）に含まれる前記共重合体及び／又は共重合体の平均分子量が１，０００〜５０，０００の範囲内にあることが好ましい。
前記添加剤中の重炭酸塩成分（ロ）に含まれる水溶性重炭酸塩が、１価金属の重炭酸塩から選ばれることが好ましい。
前記添加剤中に、追加成分として、（ハ）有機酸及びその塩、ポリリン酸及びその塩、並びに糖、及び糖アルコールから選ばれた少なくとも１種からなる硬化遅延剤、並びに、（ニ）オキシアルキレンアルキルエーテル及びポリオキシアルキレンアルキルエーテルから選ばれた少なくとも１種からなる消泡剤から選ばれた少なくとも１員を更に添加してもよい。
前記添加剤追加成分用前記硬化遅延剤（ハ）および前記消泡剤（ニ）の含有量が、前記重合体成分（イ）１００質量部に対して、それぞれ５０〜１，０００質量部、及び１〜７０質量部であることが好ましい。
The ground improvement method of the present invention comprises a cement-based solidified material containing at least 50% by mass or more of cement, and 0.1 to 25 parts by mass of (i) ethylenic unsaturated with respect to 100 parts by mass of the cement-based solidified material. A polymer component comprising at least one polymer and copolymer selected from monocarboxylic acids and ethylenically unsaturated dicarboxylic acids and at least one water-soluble salt thereof; and (b) a water-soluble bicarbonate. A ground improvement cement composition containing an additive containing a bicarbonate component containing at least one of the above is mixed with 50 to 200% of the mass of kneaded water to prepare a ground improvement cement composition slurry. The soil improvement cement composition slurry is characterized in that it is placed and mixed in the ground to be improved in a volume of 0.1 to 1.5 times the volume of the soil to be improved and hardened. .
In the ground improvement cement composition of the present invention, the ground improvement cement composition slurry further includes at least one selected from blast furnace slag, limestone powder, fly assini, silica fine powder, calcium carbonate and gypsum as an additional additive material. It may be added.
In the ground improvement method of the present invention, the ground contains a fine powder component having a soil particle diameter of 75 μm or less in a content of 50% by mass or more, or a clay component having a soil particle size of 5 μm or less is 20% by mass or more. Even when the mass ratio W / C of the mass W of the kneading water in the ground improvement cement composition slurry to the mass C of the ground improvement cement composition is 1: 0.5 to 1: 2, It is valid.
In the ground improvement method of the present invention, the mass ratio of the polymer component (I) and the bicarbonate component (B) in the additive is preferably 100: 500 to 100: 5,000. .
The polymer component (a) in the additive is a polymer or copolymer of acrylic acid, methacrylic acid, maleic acid, fumaric acid, and itaconic acid, and alkali metal salts, ammonium salts, and lower alkyl ammonium salts thereof. It is preferable to include at least one selected from
The average molecular weight of the copolymer and / or copolymer contained in the polymer component (a) in the additive is preferably in the range of 1,000 to 50,000.
The water-soluble bicarbonate contained in the bicarbonate component (b) in the additive is preferably selected from monovalent metal bicarbonates.
In the additive, as an additional component, (c) a curing retarder comprising at least one selected from organic acids and salts thereof, polyphosphoric acid and salts thereof, sugars and sugar alcohols, and (d) oxy At least one member selected from at least one antifoaming agent selected from alkylene alkyl ethers and polyoxyalkylene alkyl ethers may be further added.
The content of the curing retarder (c) for the additive additional component and the antifoaming agent (d) is 50 to 1,000 parts by mass with respect to 100 parts by mass of the polymer component (b), and It is preferable that it is 1-70 mass parts.
本発明方法は、多価金属イオンの含有量の低い陸成粘土地盤から、多価金属イオンの含有量の高い海成粘土地盤までを包含する広い範囲の各種地盤に対して優れた地盤改良効果を得ることができ、特に多価金属イオンを多量に含む海成粘土地盤に対して用いられたときに、排出スライムの海水中拡散を抑制し、海中環境の悪化を防止乃至抑制することができる。 The method of the present invention has excellent ground improvement effects for various types of ground including terrestrial clay ground with low polyvalent metal ion content to marine clay ground with high polyvalent metal ion content. In particular, when used for marine clay ground containing a large amount of polyvalent metal ions, it is possible to suppress the diffusion of the discharged slime in seawater and to prevent or suppress the deterioration of the sea environment. .
本発明に係る地盤改良方法に用いられる地盤改良セメント組成物用添加剤は、
（イ）エチレン性不飽和モノカルボン酸及びエチレン性不飽和ジカルボン酸から選ばれた少なくとも１種の重合体及び共重合体及びそれらの水溶性塩の少なくとも１種を含む重合体成分と、及び
（ロ）水溶性重炭酸塩の少なくとも１種を含む重炭酸塩成分を含み、必要により、さらに
（ハ）有機酸及びその塩、ポリリン酸及びその塩、並びに糖、及び糖アルコールから選ばれた少なくとも１種からなる硬化遅延剤、及び
（ニ）オキシアルキレンアルキルエーテル及びポリオキシアルキレンアルキルエーテルから選ばれた少なくとも１種からなる消泡剤
の１種以上を含むものである。
上記成分（イ）及び（ロ）並びに必要により成分（ハ）及び（ニ）の少なくとも１種を含む本発明の添加剤を、地盤改良セメント組成物に含有させることにより、あらゆる地盤に対し、地盤改良セメント組成物の硬化性能を低下させることなく、スライムの粘性を低下させ（流動性を向上させ）ることができ、地盤改良工事の効率を高め、その効果を向上させることができる。
The additive for ground improvement cement composition used in the ground improvement method according to the present invention,
(A) a polymer component comprising at least one polymer and copolymer selected from ethylenically unsaturated monocarboxylic acids and ethylenically unsaturated dicarboxylic acids, and water-soluble salts thereof; and (B) A bicarbonate component containing at least one water-soluble bicarbonate, and if necessary, (c) at least selected from organic acids and salts thereof, polyphosphoric acid and salts thereof, sugars, and sugar alcohols 1 type of hardening retarder, and (1) 1 or more types of the antifoamer which consists of at least 1 sort (s) chosen from oxyalkylene alkyl ether and polyoxyalkylene alkyl ether.
By adding the additive of the present invention containing at least one of the above components (a) and (b) and optionally components (c) and (d) to the ground improvement cement composition, Without reducing the hardening performance of the improved cement composition, the slime can be reduced in viscosity (improved fluidity), the efficiency of ground improvement work can be increased, and the effect thereof can be improved.
本発明方法のセメント組成物に含まれる添加剤に用いられる重合体成分（イ）は、アクリル酸、メタアクリル酸、などの不飽和モノカルボン酸及びマレイン酸、フマル酸、及びイタコン酸などの不飽和ジカルボン酸の重合体及びその少なくとも１種を含む共重合体及び／又はそれらのアルカリ金属塩、アンモニウム塩及び低級アルキルアンモニウム塩から選ばれた少なくとも１種を含むものであることが好ましく、特に、ポリアクリル酸のナトリウム塩及び／又はアンモニウム塩を含むことがより好ましい。これらの重合体成分（イ）を構成する重合体又は共重合体の質量平均分子量は１，０００〜５０，０００の範囲内にあることが好ましく、５，０００〜１０，０００の範囲内にあることがさらに好ましい。平均分子量が上記範囲内にあるとき、重合体成分（イ）は高い粘性低下の効果を示すことができる。上記質量平均分子量は、ゲルパーミエーションクロマトグラフ法（標準物質：ポリスチレンスルホン酸ナトリウム／水系）により測定することができる。
すなわち、重合体成分（イ）の平均分子量が１，０００未満の場合十分な、粘性低下の効果が得られないことがあり、またそれが、５０，０００をこえると、凝集作用が働き、粘性低下の効果がほとんど得られないことがある。
The polymer component (A) used for the additive contained in the cement composition of the method of the present invention includes unsaturated monocarboxylic acids such as acrylic acid and methacrylic acid, and unsaturated acids such as maleic acid, fumaric acid, and itaconic acid. It is preferable that the polymer contains a saturated dicarboxylic acid polymer and a copolymer containing at least one of them, and / or at least one selected from alkali metal salts, ammonium salts and lower alkylammonium salts. It is more preferable to include a sodium salt and / or an ammonium salt of an acid. The mass average molecular weight of the polymer or copolymer constituting these polymer components (a) is preferably in the range of 1,000 to 50,000, and in the range of 5,000 to 10,000. More preferably. When the average molecular weight is within the above range, the polymer component (a) can exhibit a high viscosity reducing effect. The mass average molecular weight can be measured by gel permeation chromatography (standard material: sodium polystyrene sulfonate / water system).
That is, when the average molecular weight of the polymer component (a) is less than 1,000, a sufficient viscosity reducing effect may not be obtained. In some cases, the reduction effect is hardly obtained.
本発明方法において、セメント組成物用添加剤に用いられる重炭酸塩成分（ロ）は、好ましくは、炭酸水素ナトリウム及び炭酸水素カリウムなどの炭酸水素１価金属塩から選ばれることが好ましい。成分（ロ）は、地盤改良に及ぼす土壌中の多価金属イオンの悪影響を防止する効果を有する。 In the method of the present invention, the bicarbonate component (b) used for the cement composition additive is preferably selected from monovalent metal hydrogen carbonates such as sodium hydrogen carbonate and potassium hydrogen carbonate. The component (b) has an effect of preventing adverse effects of polyvalent metal ions in the soil on the ground improvement.
重炭酸塩成分（ロ）の配合量は、重合体成分（イ）の質量、１００質量部に対し、５００〜５，０００質量部であることが好ましく、改良土の強度をさらに高めるためには、５００〜２，０００質量部であることがより好ましい。この質量比（ロ）／（イ）が、５００／１００未満であるときは、地盤中の土壌の多価金属イオンの影響により、混合土の、粘性低下の効果が不十分になることがあり、またそれが５０００／１００をこえると、地盤改良セメント組成物スラリーが短時間内に凝結することがあり、このため、地盤改良セメント組成物スラリーを深層地盤に打設・混合するときに、配管を閉塞させることがある。 The blending amount of the bicarbonate component (b) is preferably 500 to 5,000 parts by mass with respect to 100 parts by mass of the polymer component (b), and in order to further increase the strength of the improved soil. 500 to 2,000 parts by mass is more preferable. When this mass ratio (b) / (b) is less than 500/100, the effect of reducing the viscosity of the mixed soil may be insufficient due to the influence of polyvalent metal ions in the soil in the ground. In addition, if it exceeds 5000/100, the ground improvement cement composition slurry may condense within a short time. Therefore, when the ground improvement cement composition slurry is placed and mixed in the deep ground, May be blocked.
本発明の添加剤に必要により含まれる追加成分（ハ）は、有機酸及びその塩、ポリリン酸及びその塩、並びに糖及び糖アルコールから選ばれた少なくとも１種からなるものであって、地盤改良セメント組成物スラリーの分散性を高め、硬化時間を長くする硬化遅延剤として作用するものである。 The additional component (c) optionally contained in the additive of the present invention is composed of at least one selected from organic acids and salts thereof, polyphosphoric acid and salts thereof, and sugars and sugar alcohols, It acts as a curing retarder that increases the dispersibility of the cement composition slurry and lengthens the curing time.
追加成分（ハ）に用いられる有機酸及びその塩は、クエン酸、リンゴ酸、酒石酸、グルコン酸並びにこれらのナトリウム塩及びカリウム塩などの水溶性塩から選ばれることが好ましい。
追加成分（ハ）に用いられるポリリン酸及びその塩は、トリポリリン酸、テトラポリリン酸、ヘキサメタリン酸並びにこれらのナトリウム塩及びカリウム塩などの水溶性塩から選ばれることが好ましい。
追加成分（ハ）に用いられる糖及び糖アルコールは、グルコース、フラクトース、ガラクトース、サッカロース、キシロース、アビトース、リポーズ、マルトース、異性化糖等の単糖類、二糖、三糖等のオリゴ糖、デキストリン等の多糖類およびこれらを含む糖蜜類、並びに、ソルビトール等の糖アルコールから選ばれることが好ましい。
The organic acid and salt thereof used for the additional component (c) are preferably selected from citric acid, malic acid, tartaric acid, gluconic acid and water-soluble salts such as sodium salt and potassium salt thereof.
The polyphosphoric acid and salt thereof used for the additional component (c) are preferably selected from tripolyphosphoric acid, tetrapolyphosphoric acid, hexametaphosphoric acid and water-soluble salts such as sodium salt and potassium salt thereof.
The sugar and sugar alcohol used in the additional component (c) are monosaccharides such as glucose, fructose, galactose, saccharose, xylose, abitose, repose, maltose, isomerized sugar, oligosaccharides such as disaccharide and trisaccharide, dextrin, etc. It is preferable to be selected from these polysaccharides and molasses containing them, and sugar alcohols such as sorbitol.
追加成分（ハ）は、硬化時間のコントロールの観点から、クエン酸ナトリウム、トリポリリン酸ナトリウム、及びサッカロースから選ばれた１種以上を含むことが好ましい。
追加成分（ハ）の配合量は、重合体成分（イ）１００質量部に対し、５０〜１，０００質量部であることが好ましく、２００〜８００質量部であることがより好ましい。追加成分（ハ）の配合量が、５０質量部以下では、地盤改良工事における硬化時間の遅延効果が不十分になることがあり、またそれが１，０００質量部をこえると、十分な強度が得られないことがある。
The additional component (c) preferably contains one or more selected from sodium citrate, sodium tripolyphosphate, and saccharose from the viewpoint of controlling the curing time.
The compounding amount of the additional component (c) is preferably 50 to 1,000 parts by mass, and more preferably 200 to 800 parts by mass with respect to 100 parts by mass of the polymer component (a). If the blending amount of the additional component (c) is 50 parts by mass or less, the effect of delaying the curing time in the ground improvement work may be insufficient, and if it exceeds 1,000 parts by mass, sufficient strength is obtained. It may not be obtained.
本発明方法において、追加消泡剤成分（ニ）としてオキシアルキレンアルキルエーテル及びポリオキシアルキレンアルキルエーテルから選ばれた少なくとも１種が用いられる。これらの化合物は、下記一般式（１）により表される。
Ｒ−Ｏ（ＰＯ）m （ＥＯ）n Ｈ （１）
〔但し、式（１）中、Ｒは水素原子、または、６〜２４個の炭素原子を含むアルキル基、アルケニル基又はアリール基を表し、ＰＯはオキシプロピレン基を表し、ＥＯはオキシエチレン基を表し、ｍは１〜５０の整数を表し、ｎは０〜５０の整数を表す〕。
式（１）の化合物において、Ｒが水素原子であるか、或はＣ6 −Ｃ18アルキル基であることが好ましい。Ｒが水素原子の場合、式（１）の化合物はオキシプロピレン、ポリオキシプロピレン、エチレン、ポリオキシエチレンなどのオキシアルキレン及びポリオキシアルキレンを包含する。
In the method of the present invention, at least one selected from oxyalkylene alkyl ethers and polyoxyalkylene alkyl ethers is used as the additional antifoam component (d). These compounds are represented by the following general formula (1).
R—O (PO) m (EO) n H (1)
[In the formula (1), R represents a hydrogen atom or an alkyl group, an alkenyl group or an aryl group containing 6 to 24 carbon atoms, PO represents an oxypropylene group, and EO represents an oxyethylene group. M represents an integer of 1 to 50, and n represents an integer of 0 to 50].
In the compound of the formula (1), R is preferably a hydrogen atom or a C 6 -C 18 alkyl group. When R is a hydrogen atom, the compound of formula (1) includes oxyalkylenes such as oxypropylene, polyoxypropylene, ethylene, polyoxyethylene, and polyoxyalkylene.
本発明方法に用いられる前記追加成分（ニ）として好ましい消泡剤化合物としては、Ｒがラウリル基でありｍが３、ｎが０のポリオキシプロピレン（ｍ＝３）ラウリルエーテル、Ｒがラウリル基でありｍが０、ｎが１のオキシエチレンラウリルエーテルなどが用いられる。
本発明方法に用いられる前記添加剤において、追加成分（ニ）の配合量は、重合体成分（イ）１００質量部に対し、追加成分（ニ）が１〜７０質量部であることが好ましく、より好ましくは１０〜５０質量部であることがより好ましい。
Preferred antifoam compounds as the additional component (d) used in the method of the present invention include polyoxypropylene (m = 3) lauryl ether in which R is a lauryl group, m is 3 and n is 0, and R is a lauryl group. And m is 0 and n is 1, for example, oxyethylene lauryl ether.
In the additive used in the method of the present invention, the amount of the additional component (d) is preferably 1 to 70 parts by mass of the additional component (d) with respect to 100 parts by mass of the polymer component (b). More preferably, it is 10-50 mass parts.
本発明方法に用いられる地盤改良セメント組成物用添加剤には、必要により、前記成分（イ）、（ロ）及び追加成分（ハ）、（ニ）に加えて、従来の地盤改良セメント組成物に用いられているＡＥ剤、ＡＥ減水剤、高性能減水剤、遅延剤、早強剤、促進剤、起泡剤、発泡剤、消泡剤、増粘剤、防水剤等の公知の添加剤が配合されていてもよい。 If necessary, the additive for the ground improvement cement composition used in the method of the present invention includes the conventional ground improvement cement composition in addition to the components (A) and (B) and the additional components (C) and (D). Known additives such as AE agent, AE water reducing agent, high performance water reducing agent, retarder, early strengthening agent, accelerator, foaming agent, foaming agent, antifoaming agent, thickener, waterproofing agent, etc. May be blended.
本発明方法に用いられる地盤改良セメント組成物は、少なくとも５０質量％のセメントを含むセメント系固化材と、このセメント系固化材１００質量部に対し、０．１〜２５質量部の、前記地盤改良用セメント組成物用添加剤とを含むものである。
本発明方法に使用されるセメントとしては、普通、早強、超早強、中庸熱、耐硫酸塩等の各種ポルトランドセメント、高炉セメント、シリカセメント、フライアッシュセメントなどＪＩＳに規定されているものを包含し、本発明の課題解決に支障がない限り、その種類には、格別の制限はない。
The ground improvement cement composition used in the method of the present invention is a cement-based solidified material containing at least 50% by mass of cement, and 0.1 to 25 parts by mass of the ground-based improvement with respect to 100 parts by mass of the cement-based solidified material. And an additive for cement composition.
As the cement used in the method of the present invention, those specified in JIS such as various portland cements such as normal, early strength, super early strength, moderate heat, sulfate resistance, blast furnace cement, silica cement, fly ash cement and the like. As long as it is included and there is no problem in solving the problems of the present invention, there is no particular limitation on the type.
本発明方法に用いられる地盤改良セメント組成物には、追加添加材料が５０質量％以下の含有量で含まれていてもよく、特に高粘性を有する土質に対しては、本発明の地盤改良セメント組成物用添加剤の配合量に応じて、３０〜５０質量％の追加添加材料が含まれていることが好ましい。この追加添加材料としては、高炉スラグ、石灰石粉、フライアッシュ、シリカ微粉末、炭酸カルシウム及び石膏から選ばれた少なくとも１種が用いられ、必要によりさらに石炭灰、溶融スラグ、ガラスカレットなどが含まれていてもよく、シリカ微粉末は、フュームドシリカを包含する。高炉スラグ、フライアッシュ及びヒュームドシリカはいわゆるポゾラン反応やマイクロフィラー効果を奏する添加材であり、長期強度を増大させる効果がある。さらに、これらの追加添加材料は、セメント粒子と添加材の粒子が均一に分散し、凝集を防止するため、材料分離を抑制する効果を発揮することができる。またフライアッシュは球状の粉末で、そのベアリング効果により、セメント組成物の流動性を向上させることができる。 The ground improvement cement composition used in the method of the present invention may contain an additional additive material in a content of 50% by mass or less, and particularly for soil having high viscosity, the ground improvement cement of the present invention. It is preferable that 30 to 50% by mass of an additional additive material is included depending on the amount of the additive for the composition. As this additional additive material, at least one selected from blast furnace slag, limestone powder, fly ash, fine silica powder, calcium carbonate and gypsum is used, and if necessary, coal ash, molten slag, glass cullet and the like are included. The fine silica powder includes fumed silica. Blast furnace slag, fly ash, and fumed silica are additives that exhibit a so-called pozzolanic reaction and microfiller effect, and have the effect of increasing long-term strength. Further, these additional additive materials can exhibit the effect of suppressing material separation because the cement particles and the additive particles are uniformly dispersed to prevent aggregation. Further, fly ash is a spherical powder, and the fluidity of the cement composition can be improved by its bearing effect.
本発明方法に用いられる地盤改良セメント組成物において、セメント系固化材と、前記地盤改良セメント組成物用添加剤との配合質量比は、１００：０．１〜１００：２５であることが好ましく、１００：０．５〜１００：１０であることがより好ましく、１００：１〜１００：５であることがさらに好ましい。またセメント系固化材１００質量部に対し、添加剤の各成分の配合量は、
重合体成分（イ）：０．０１〜２．０質量部、
重炭酸塩成分（ロ）：０．１〜１０．０質量部、
追加硬化遅延剤成分（ハ）：０〜１０質量部、
追加消泡剤成分（ニ）：０〜１．０質量部、
であることが好ましい。
セメント系固化材１００質量部に対して、本発明の添加剤の配合量が０．１質量部未満であると本発明の、添加剤の効果が不十分になることがあり、またそれが２５質量部をこえると、セメント系固化材の地盤改良効果が不十分になることがある。
In the ground improvement cement composition used in the method of the present invention, the blending mass ratio of the cement-based solidifying material and the additive for ground improvement cement composition is preferably 100: 0.1 to 100: 25, 100: 0.5 to 100: 10 is more preferable, and 100: 1 to 100: 5 is even more preferable. Moreover, with respect to 100 parts by mass of the cement-based solidifying material,
Polymer component (I): 0.01 to 2.0 parts by mass,
Bicarbonate component (b): 0.1 to 10.0 parts by mass,
Additional curing retarder component (C): 0 to 10 parts by mass,
Additional antifoam component (d): 0 to 1.0 part by mass,
It is preferable that
When the compounding amount of the additive of the present invention is less than 0.1 parts by mass with respect to 100 parts by mass of the cement-based solidifying material, the effect of the additive of the present invention may be insufficient, and 25 If the mass part is exceeded, the ground improvement effect of the cement-based solidified material may be insufficient.
本発明の地盤改良方法において、前記地盤改良セメント組成物を、その質量の５０〜２００％、好ましくは６０〜１５０％の混練水に混合して地盤改良セメント組成物スラリーを調製し、この地盤改良セメント組成物スラリーを、改良すべき地盤中に、改良対象土の容積の０．１〜１．５倍の容積、をもって打設・混合し、硬化させる。
地盤改良セメント組成物スラリー中の混練水の量が、地盤改良セメント組成物の質量の５０％未満のときは、得られるスラリーの粘性が増大しポンプ圧送が困難になりワーカビリティの悪化を生ずることがあり、またそれが２００％をこえると、材料分離が懸念され、改良土の、強度低下やバラツキを生ずることがある。
また、地盤改良セメント組成物スラリーの打設量が、改良対象土の容量の０．１倍以下であると、地盤改良セメント組成物スラリーと、改良対象土の混合不良が生じ品質が悪化することがある。
In the ground improvement method of the present invention, the ground improvement cement composition is mixed with 50 to 200%, preferably 60 to 150%, of the mass of kneaded water to prepare a ground improvement cement composition slurry. The cement composition slurry is placed and mixed in the ground to be improved at a volume of 0.1 to 1.5 times the volume of the soil to be improved, and cured.
If the amount of kneading water in the ground improvement cement composition slurry is less than 50% of the mass of the ground improvement cement composition, the viscosity of the resulting slurry will increase and pumping will be difficult, resulting in poor workability. In addition, if it exceeds 200%, there is a concern about material separation, and the strength of the improved soil may be reduced or may vary.
In addition, if the amount of the ground improvement cement composition slurry is 0.1 times or less the capacity of the soil to be improved, the ground improvement cement composition slurry and the soil to be improved are poorly mixed and the quality is deteriorated. There is.
硬化した改良土の品質を悪くする因子のうち、第一の因子として、改良対象土の特性と使用するセメント組成物の相性があることが、本発明に伴う試験で明らかとなった。土の土粒子径が７５μｍ以下の細粒土の含有率が３０％を超える地盤（参考文献あり）では、強度発現効果が悪くなる。その要因として混ざり具合が重要である。混ざり具合は、土の土粒子径が５μｍ以下の粘土分の含有率が４０％を超える地盤では、コロイドの電荷作用と凝集により偽凝結を生じ（流動性を失った状態）になり、攪拌する施工機械の攪拌機構の能力を十分に発揮できないまま硬化してしまい、セメント組成物スラリーの混練不足を招くことがある。このような場合には、本発明の地盤改良セメント組成物を使用することにより、混練直後から３０分までの固まらない状態の流体、いわゆるビンガム流体のせん断力を軽減することが可能になり、混ざり具合を改善することができる。従って、設備能力を十分に発揮でき、工程の遅延や改良物の悪化を防止できる。本発明方法による、海成粘土を用いた試験および内陸型粘性土を用いた試験において、本発明方法に用いられる地盤改良セメント組成物スラリーと従来の固化材スラリーとを比較すると、本発明方法において用いられる地盤改良セメント組成物スラリーによるものが、より良好な成果が得られ、混合後３０分程度まではスライムの低粘性が確保でき、ワーカビリティが著しく改善できることが確認された。（後記実施例１１参照） Among the factors that deteriorate the quality of the hardened improved soil, the first factor has revealed that the properties of the soil to be improved and the cement composition to be used are compatible with the test according to the present invention. In the ground where the content of fine-grained soil having a soil particle diameter of 75 μm or less exceeds 30% (there is a reference), the strength development effect is deteriorated. The mixing condition is important as the factor. As for the mixing condition, when the soil content of the soil has a soil particle diameter of 5 μm or less and the soil content exceeds 40%, a colloidal charge action and agglomeration result in the formation of false coagulation (a state in which fluidity has been lost), and stirring is performed. It may harden | cure without fully exhibiting the capability of the stirring mechanism of a construction machine, and may cause the kneading | mixing shortage of a cement composition slurry. In such a case, by using the ground improvement cement composition of the present invention, it becomes possible to reduce the shearing force of the fluid that does not solidify immediately after kneading until 30 minutes, that is, the so-called Bingham fluid, and is mixed. The condition can be improved. Therefore, the facility capacity can be fully exhibited, and the delay of the process and the deterioration of the improved product can be prevented. In the method using the marine clay and the test using inland type clay soil according to the method of the present invention, the ground improved cement composition slurry used in the method of the present invention and the conventional solidified material slurry are compared. It was confirmed that a better result was obtained with the ground improvement cement composition slurry used, and that the low viscosity of the slime can be secured up to about 30 minutes after mixing, and the workability can be remarkably improved. (See Example 11 below)
本発明の地盤改良方法において、地盤が、土粒子径７５μｍ以下の細粒分を５０質量％以上の含有率で含むか、又は５μｍ以下の土粒子径を有する粘土分を２０質量％以上の含有率で含む場合、地盤改良セメント組成物スラリーにおける混練水の質量Ｗの、地盤改良セメント組成物の質量Ｃに対する質量比Ｗ／Ｃを１：０．５〜１：２にコントロールすることが好ましい。
また、上記の場合、地盤改良セメント組成物スラリーの体積Ｖｍの、改良すべき地盤の土壌体積Ｖに対する比Ｖｍ／Ｖは、０．１〜１．５にコントロールすることが好ましい。
In the ground improvement method of the present invention, the ground contains a fine particle having a soil particle diameter of 75 μm or less in a content of 50% by mass or more, or a clay having a soil particle diameter of 5 μm or less contains 20% by mass or more. When the ratio is included, it is preferable to control the mass ratio W / C of the mass W of the kneaded water in the ground improvement cement composition slurry to the mass C of the ground improvement cement composition to 1: 0.5 to 1: 2.
In the above case, the ratio Vm / V of the volume Vm of the ground improvement cement composition slurry to the soil volume V of the ground to be improved is preferably controlled to 0.1 to 1.5.
本発明の地盤改良方法は、上記のように、粒径が７５μｍ以下の細粒土分の含有率が重量比で３０％以上を超える土質、好ましくは、粒径が７５μｍ以下の細粒土分の含有率が重量比で５０％以上を超える土質または、土粒子径が５μｍ以下の粘土分の含有率が２０％以上を超える土質、最も好ましくは７５μｍ以下の細粒土分の含有率が重量比で７０％以上を超える土質または、土粒子径が５μｍ以下の粘土分の含有率が４０％以上を超える土質に対し、最も有効に用いられる。 As described above, the ground improvement method of the present invention is a soil whose content of fine-grained soil having a particle size of 75 μm or less exceeds 30% by weight, preferably a fine-grained soil having a particle size of 75 μm or less. The soil content is more than 50% or more by weight, or the soil content is more than 20%, and most preferably the fine soil content is 75μm or less. It is most effectively used for soils having a ratio exceeding 70% or more, or soils having a soil particle diameter of more than 40%.
本発明の地盤改良方法が用いられる環境には、地表から直接もしくは所定の深さの施工深度からセメント組成物スラリーと土とを混合攪拌する陸上施工で用いられる場合と、海面上で海底から直接もしくは所定の深さの施工深度からセメント組成物スラリーと土とを混合攪拌する海上施工で使用される場合とがある。これらのうち、海上施工においては、セメント組成物スラリーと土とが混合されたスライムは海水中に排出されるため、周辺海域の汚濁が懸念される。特に海底地盤で多く見られる海成粘土では、前述のように、スライムの性状において、改良土の品質やワーカビリティーを確保する上で粘性を低く抑える必要があり、このため排出されたスライムによる周辺海域の汚濁が生ずる可能性がある。本発明方法に用いられる地盤改良セメント組成物スラリーと、土（海成粘土）とを用いた実験では、混合土の粘性は、前述のよう低く抑えることができた。この混合土を海水中に投入し、濁度測定を行ったところ、海水中に海成粘土のみを投入した場合と比較しても大幅に濁度の低下、すなわち混合土の拡散を抑制し得ることが明らかになった。（後記実施例１２参照） In the environment where the ground improvement method of the present invention is used, there are a case where it is used in land construction where the cement composition slurry and soil are mixed and stirred directly from the ground surface or from a construction depth of a predetermined depth, and directly from the sea floor on the sea surface. Or it may be used by the marine construction which mixes and stirs a cement composition slurry and soil from the construction depth of a predetermined depth. Among these, in the offshore construction, the slime mixed with the cement composition slurry and the soil is discharged into the seawater, so there is a concern about contamination of the surrounding sea area. Especially for marine clay, which is often found on the seabed, it is necessary to keep the viscosity low in order to ensure the quality and workability of the improved soil in the properties of the slime. May occur. In the experiment using the ground improvement cement composition slurry used in the method of the present invention and soil (marine clay), the viscosity of the mixed soil could be kept low as described above. When this mixed soil was put into seawater and turbidity measurement was performed, even if compared with the case where only marine clay was thrown into seawater, the decrease in turbidity, that is, the diffusion of mixed soil can be suppressed. It became clear. (See Example 12 below)
本発明を下記実施例によりさらに説明する。 The invention is further illustrated by the following examples.
実施例１〜９及び比較例１〜１２
実施例１〜９及び比較例１〜１２の各々において、下記成分（イ）〜（ニ）を用いて、地盤改良セメント組成物用添加剤を調製し、これを、下記セメント系固化材に混合して地盤改良セメント組成物を調製し、この地盤改良セメント組成物から調製された地盤改良セメント組成物スラリーを下記記載の試料土に混合して水硬性セメント混合物を調製した。
Examples 1-9 and Comparative Examples 1-12
In each of Examples 1 to 9 and Comparative Examples 1 to 12, an additive for ground improvement cement composition was prepared using the following components (i) to (d), and this was mixed with the following cement-based solidifying material. Then, the ground improved cement composition was prepared, and the ground improved cement composition slurry prepared from the ground improved cement composition was mixed with the sample soil described below to prepare a hydraulic cement mixture.
地盤改良セメント組成物用添加剤の成分
〔成分（イ）〕
・（イ−１）：「ポリアクリル酸」（質量平均分子量：８０００）
・（イ−２）：「ポリアクリル酸ナトリウム塩」（質量平均分子量：８０００）
〔成分（ロ）〕
・（ロ−１）：炭酸水素ナトリウム
・（ロ−２）：炭酸水素カリウム
〔成分（ハ）〕
・（ハ−１）：クエン酸三ナトリウム
・（ハ−２）：トリポリリン酸ナトリウム
〔成分（ニ）〕
・（ニ−１）：オキシアルキレンアルキルエーテル（商標：ＳＮデフォーマー１５−Ｐ 、サンノプコ社製）
・（ニ−２）：ポリオキシアルキレンアルキルエーテル（商標：消泡剤Ｎｏ．８、花王 製）
Ingredients for additives for ground improvement cement composition [component (I)]
-(I-1): "Polyacrylic acid" (mass average molecular weight: 8000)
-(I-2): "Polyacrylic acid sodium salt" (mass average molecular weight: 8000)
[Ingredients (b)]
(B-1): Sodium bicarbonate (B-2): Potassium bicarbonate [component (C)]
(C-1): trisodium citrate (c-2): sodium tripolyphosphate [component (d)]
(D-1): oxyalkylene alkyl ether (trademark: SN deformer 15-P, manufactured by San Nopco)
-(D-2): polyoxyalkylene alkyl ether (trademark: antifoam No. 8, manufactured by Kao)
セメント系固化材
・セメント：普通ポルトランドセメント
添加材
・高炉スラグ：エスメント４０００（新日本化学製）
Cement-based solidification material ・ Cement: Ordinary Portland cement additive ・ Blast furnace slag: Esment 4000 (Nippon Chemical Co., Ltd.)
実験対象の土
・内陸部粘性土：茨城県つくば地方の工事現場で採取（湿潤密度ρｔ＝１．６６ｇ／
cm3 、含水比ωｎ＝４９．０％）
・海成粘土 ：東京都江東区砂町の工事現場で採取（湿潤密度ρｔ＝１．５６ｇ／
cm3 、含水比ωｎ＝７２．４％）
Soil subject to experiment ・ Inland viscous soil: collected at a construction site in Tsukuba, Ibaraki Prefecture (wet density ρt = 1.66 g /
cm 3 , water content ωn = 49.0%)
・ Marine clay: collected at construction site in Sunamachi, Koto-ku, Tokyo (wet density ρt = 1.56g /
cm 3 , water content ωn = 72.4%)
実施例１〜９及び比較例１〜１２の各々において、表１又は２に記載のセメント系固化材と、添加剤成分（イ）〜（ニ）とを、表１又は２に記載の配合量（質量部）で調合し、得られたセメント組成物（合計１００質量部）と水とを、質量比２００／３００の配合比で、家庭用ハンドミキサーで混合し、セメント組成物スラリー（以下セメントミルクと記す）を調製した。得られたセメントミルクと、土とを配合重量比２００／３００（容積比１４５〜１４７／１８８〜１９２）で、家庭用ハンドミキサーにより混合し、水硬性セメント混合物を調製した。 In each of Examples 1 to 9 and Comparative Examples 1 to 12, the cement-based solidifying material described in Table 1 or 2 and the additive components (i) to (d) are blended in amounts described in Table 1 or 2. The resulting cement composition (100 parts by mass in total) and water were mixed with a household hand mixer at a mass ratio of 200/300 to obtain a cement composition slurry (hereinafter referred to as cement). (Referred to as milk). The obtained cement milk and soil were mixed at a blending weight ratio of 200/300 (volume ratio of 145 to 147/188 to 192) by a household hand mixer to prepare a hydraulic cement mixture.
上記水硬性セメント混合物を、下記試験に供した。
（１）分散性／粘性試験
水硬性セメント混合物をフローコーン（φ５０×高さ５１mm）に入れ、フローコーンを持ち上げ水硬性セメント混合物の拡がりをもって分散性／粘性の指標とした。結果を、拡がりの径１６０mm以上を「Ｓ」、１４０mm以上１６０mm未満を「Ａ」、１２０〜１４０mmを「Ｂ」、１００〜１２０mmを「Ｃ」、７０〜１００mmを「Ｄ」、７０mm以下を「Ｅ」と６段階に判定し、表記した。
（２）硬化性試験
水硬性セメント混合物を、その調製から４８時間静置した後、水硬性セメント混合物に５kg／cm2 の荷重をかけ、変形の有無を目視により観察し、変形しないものを「○」、変形するものを「×」と判定表記した。
実施例１〜９の試験結果を表１に示し、比較例１〜１２の試験結果を表２に示す。
The hydraulic cement mixture was subjected to the following test.
(1) Dispersibility / viscosity test The hydraulic cement mixture was placed in a flow cone (φ50 × height 51 mm), the flow cone was lifted, and the spread of the hydraulic cement mixture was used as an index of dispersibility / viscosity. The result is “S” for an expanded diameter of 160 mm or more, “A” for 140 mm or more and less than 160 mm, “B” for 120 to 140 mm, “C” for 100 to 120 mm, “D” for 70 to 100 mm, and “70” for 70 mm or less. E ”was determined in 6 stages and indicated.
(2) Curability test After the hydraulic cement mixture was allowed to stand for 48 hours from its preparation, a load of 5 kg / cm 2 was applied to the hydraulic cement mixture, and the presence or absence of deformation was visually observed. “○”, and those that deformed were marked as “x”.
The test results of Examples 1 to 9 are shown in Table 1, and the test results of Comparative Examples 1 to 12 are shown in Table 2.
表１及び２の註
＊ＮＳＦ：ナフタレンスルホン酸ホルマリン縮合物Ｎａ塩
＊Ｎａ2 ＣＯ3 ：炭酸ナトリウム
＊Ｎａ2 ＳＯ4 ：硫酸ナトリウム
Tables 1 and 2 * NSF: Naphthalenesulfonic acid formalin condensate Na salt * Na 2 CO 3 : Sodium carbonate * Na 2 SO 4 : Sodium sulfate
実施例１０及び１１並びに比較例１３
実施例１０，１１及び比較例１３の各々において、下記成分材料を用い、表３に記載の配合量で配合して、セメント組成物を調製した。
Examples 10 and 11 and Comparative Example 13
In each of Examples 10 and 11 and Comparative Example 13, the following component materials were used and blended in the blending amounts shown in Table 3 to prepare cement compositions.
添加剤成分
（イ）：「ポリアクリル酸ナトリウム塩」（質量平均分子量：８０００）
（ロ）：炭酸水素ナトリウム
（ハ）：クエン酸三ナトリウム
（ニ）：オキシアルキレンアルキルエーテル（商標：アデカネート、旭電化工業製）
セメント系固化材成分
セメント：普通ポルトランドセメント（住友大阪セメント製）
石膏：無水石膏（日本軽金属製）
Additive component (I): "Polyacrylic acid sodium salt" (mass average molecular weight: 8000)
(B): Sodium hydrogen carbonate (c): Trisodium citrate (d): Oxyalkylene alkyl ether (Trademark: Adecanate, manufactured by Asahi Denka Kogyo)
Cement-based solidifying material component Cement: Ordinary Portland cement (manufactured by Sumitomo Osaka Cement)
Gypsum: Anhydrous gypsum (Nippon Light Metal)
セメント組成物スラリー配合及び投入量
硬化材スラリー配合：Ｗ／Ｃ＝１００％（質量比）Ｗ：混練水（イオン交換水）、Ｃ：硬化材
硬化材スラリー投入量：上記硬化材配合の硬化材スラリー（Ｖｍ）を下記供試土（Ｖ）に体積比でＶｍ／Ｖ＝０．５となるよう計量し投入した。
Cement composition slurry blending and charging amount Curing material slurry blending: W / C = 100% (mass ratio) W: Kneading water (ion exchange water), C: Curing material Curing material slurry charging amount: Curing material blending the above curing material The slurry (Vm) was weighed and introduced into the following test soil (V) so that Vm / V = 0.5 by volume.
試料土
内陸粘土：埼玉県所沢粘性土
湿潤密度ρｔ＝１．８３ｇ／cm3 、含水比ωｎ＝３７．３％
７５μｍ以下含有率Ｆｓ＝６６％、５μｍ以下含有率Ｆｓ＝４９％
海成粘土：東京都江東区砂町粘性土
湿潤密度ρｔ＝１．５４ｇ／cm3 、含水比ωｎ＝７１．２％
７５μｍ以下含有率Ｆｓ＝９９％、５μｍ以下含有率Ｆｓ＝５３％
Sample soil Inland clay: Tokorozawa clay soil, Saitama
Wet density ρt = 1.83 g / cm 3 , moisture content ωn = 37.3%
75 μm or less content Fs = 66%, 5 μm or less content Fs = 49%
Marine clay: sandy clay soil, Koto-ku, Tokyo
Wet density ρt = 1.54 g / cm 3 , water content ratio ωn = 71.2%
75 μm or less content Fs = 99%, 5 μm or less content Fs = 53%
改良土の作製
改良土の作製に当たっては、所定量の試料土とセメント組成物スラリーを計量混合し、ホバート型ミキサーで６分間混合攪拌を行った。
Preparation of improved soil In preparation of improved soil, a predetermined amount of sample soil and cement composition slurry were weighed and mixed, and mixed and stirred for 6 minutes with a Hobart mixer.
改良土の粘性試験
改良土の粘性試験において、簡易ベーン試験装置を用いて混合攪拌直後からの改良土のベーンせん断強さの経時変化を測定した。
測定結果を図１及び図２に示す。
実施例１０において内陸粘土に対し、優れた改良結果が得られ、実施例１０及び１１において、特に実施例１１において、海成粘土に対し、優れた改良結果が得られた。
Improved soil viscosity test In the improved soil viscosity test, the time-dependent change in vane shear strength of the improved soil immediately after mixing and stirring was measured using a simple vane test device.
The measurement results are shown in FIGS.
In Example 10, an excellent improvement result was obtained for inland clay, and in Examples 10 and 11, particularly in Example 11, an excellent improvement result was obtained for marine clay.
実施例１２
（１）下記組成のセメント組成物を調製した。
セメント：普通ポルトランドセメント ９７．４５％
添加剤
（イ）：「ポリアクリル酸」（質量平均分子量：８０００） ０．１５％
（ロ）：炭酸水素ナトリウム １．５５％
（ハ）：クエン酸三ナトリウム ０．７５％
（ニ）：ポリオキシアルキレンアルキルエーテル ０．１０％
（商標：ＳＮデフォーマー１５−Ｐ、サンノプコ社製）
（２）供試土は下記のとおりであった。
・海成粘土：東京都江東区砂町の工事現場で採取（湿潤密度ρｔ＝１．５６ｇ／cm3 、 含水比ωｎ＝７２．４％）
Example 12
(1) A cement composition having the following composition was prepared.
Cement: Ordinary Portland cement 97.45%
Additive (I): “Polyacrylic acid” (mass average molecular weight: 8000) 0.15%
(B): Sodium bicarbonate 1.55%
(C): Trisodium citrate 0.75%
(D): Polyoxyalkylene alkyl ether 0.10%
(Trademark: SN deformer 15-P, manufactured by San Nopco)
(2) The test soil was as follows.
・ Marine clay: collected at construction site in Sunamachi, Koto-ku, Tokyo (wet density ρt = 1.56g / cm 3 , moisture content ωn = 72.4%)
（３）試験
改良土の水中（海水中）での拡散状態を確認するため、下記方法による濁度測定試験を実施した。セメント組成物２００質量部と水３００質量部とを家庭用ハンドミキサーで混合し、セメント組成物スラリーを調製した。上記セメント組成物スラリー２００質量部と粘性土２００質量部（容積比１４５／１２８）を家庭用ハンドミキサーで混合し、改良土を調製した。この改良土２０ｇを１リットルビーカーに取り、このビーカーにイオン交換水又は海水９８０ｇを静かに投入し、その上層液を５０ｇ採取し、投入直後（攪拌前）の濁度を測定した。更にビーカー内を攪拌装置で攪拌（３００rpm ×１min ）し、その上層液５０ｇを採取し３００rpm 攪拌後の濁度を測定した。
（濁度）
濁度の測定は、島津製作所製 紫外分光光度計「ＵＶ−１６０Ａ」を用いて行った。
濁度の指標として、海成粘土を水に分散させた状態の濁度を指標とした。
＜検量線＞
５００ppm ：海成粘土０．０５％／イオン交換水
１０００ppm ：海成粘土０．１０％／イオン交換水
２０００ppm ：海成粘土０．２０％／イオン交換水
供試海成粘土の濁度の指標を表４に示し、海水中の海成粘土の濁度と吸光度との関係図を図３に示し、試験結果を表５に示す。
(3) Test In order to confirm the diffusion state of the improved soil in water (in seawater), a turbidity measurement test was carried out by the following method. 200 parts by mass of the cement composition and 300 parts by mass of water were mixed with a household hand mixer to prepare a cement composition slurry. 200 parts by mass of the above cement composition slurry and 200 parts by mass of viscous soil (volume ratio 145/128) were mixed with a household hand mixer to prepare improved soil. 20 g of this improved soil was taken in a 1 liter beaker, and 980 g of ion-exchanged water or seawater was gently put into this beaker, 50 g of the upper layer liquid was sampled, and turbidity was measured immediately after the addition (before stirring). Further, the inside of the beaker was stirred with a stirrer (300 rpm × 1 min), 50 g of the upper layer liquid was collected, and the turbidity after stirring at 300 rpm was measured.
(Turbidity)
The turbidity was measured using an ultraviolet spectrophotometer “UV-160A” manufactured by Shimadzu Corporation.
As an index of turbidity, the turbidity of marine clay dispersed in water was used as an index.
<Calibration curve>
500ppm: Marine clay 0.05% / ion-exchanged water 1000ppm: Marine clay 0.10% / ion-exchanged water 2000ppm: Marine clay 0.20% / ion-exchanged water Index of turbidity of test marine clay Table 4 shows the relationship between the turbidity and absorbance of marine clay in seawater, and FIG. 3 shows the test results.
表５及び図３から明らかなように、本発明方法による実施例１２の海成粘土の改良土は、海水中への拡散が少なく、本発明方法が海底における海成地盤の改良に有効であることが確認された。 As is apparent from Table 5 and FIG. 3, the improved soil of the marine clay of Example 12 according to the method of the present invention has little diffusion into seawater, and the method of the present invention is effective for improving the marine ground on the seabed. It was confirmed.
本発明の地盤改良方法は、地盤（内陸及び多価金属イオンを多く含む粘土地盤）の改良において、高い地盤改良効果を示し、特に多価金属イオンを多く含む（例えば海成粘土）地盤に対し、地盤改良工事を施すときにも、排出スライムの海水中拡散を抑制し、海中環境の悪化を防止乃至抑制することができるものであって、極めて高い実用性を有するものである。 The ground improvement method of the present invention shows a high ground improvement effect in the improvement of the ground (inland and clay ground containing a large amount of polyvalent metal ions), especially for ground containing a large amount of polyvalent metal ions (eg marine clay). Even when ground improvement work is performed, it is possible to suppress the diffusion of discharged slime in seawater and prevent or suppress deterioration of the sea environment, and has extremely high practicality.
Claims (9)
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| JP2009150121A (en) * | 2007-12-20 | 2009-07-09 | Nippon Solid Co Ltd | Method of improving soft ground |
| JP2009286655A (en) * | 2008-05-29 | 2009-12-10 | Takemoto Oil & Fat Co Ltd | Powdery premixed cement composition for foundation improvement |
| CN107936973A (en) * | 2017-11-05 | 2018-04-20 | 长沙秋点兵信息科技有限公司 | A kind of heavy-metal contaminated soil CaCO3The preparation method of/C renovation agents |
| WO2020027191A1 (en) * | 2018-08-01 | 2020-02-06 | 花王株式会社 | Method for improving ground |
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|---|---|---|---|---|
| JP2009150121A (en) * | 2007-12-20 | 2009-07-09 | Nippon Solid Co Ltd | Method of improving soft ground |
| JP2009286655A (en) * | 2008-05-29 | 2009-12-10 | Takemoto Oil & Fat Co Ltd | Powdery premixed cement composition for foundation improvement |
| CN107936973A (en) * | 2017-11-05 | 2018-04-20 | 长沙秋点兵信息科技有限公司 | A kind of heavy-metal contaminated soil CaCO3The preparation method of/C renovation agents |
| WO2020027191A1 (en) * | 2018-08-01 | 2020-02-06 | 花王株式会社 | Method for improving ground |
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