JP6781958B2 - How to make improved soil - Google Patents
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- JP6781958B2 JP6781958B2 JP2017071514A JP2017071514A JP6781958B2 JP 6781958 B2 JP6781958 B2 JP 6781958B2 JP 2017071514 A JP2017071514 A JP 2017071514A JP 2017071514 A JP2017071514 A JP 2017071514A JP 6781958 B2 JP6781958 B2 JP 6781958B2
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- 239000002689 soil Substances 0.000 title claims description 117
- UIIMBOGNXHQVGW-UHFFFAOYSA-M Sodium bicarbonate Chemical compound [Na+].OC([O-])=O UIIMBOGNXHQVGW-UHFFFAOYSA-M 0.000 claims description 50
- 239000006185 dispersion Substances 0.000 claims description 44
- 239000004568 cement Substances 0.000 claims description 37
- 239000000463 material Substances 0.000 claims description 35
- 229910000030 sodium bicarbonate Inorganic materials 0.000 claims description 25
- 235000017557 sodium bicarbonate Nutrition 0.000 claims description 25
- 239000002270 dispersing agent Substances 0.000 claims description 23
- 238000004519 manufacturing process Methods 0.000 claims description 20
- 239000003795 chemical substances by application Substances 0.000 claims description 19
- 150000001768 cations Chemical class 0.000 claims description 12
- -1 alkali metal bicarbonate Chemical class 0.000 claims description 6
- 238000005259 measurement Methods 0.000 claims description 6
- 229910052783 alkali metal Inorganic materials 0.000 claims description 5
- 229910000288 alkali metal carbonate Inorganic materials 0.000 claims description 5
- 150000008041 alkali metal carbonates Chemical class 0.000 claims description 5
- 238000002360 preparation method Methods 0.000 claims description 3
- 239000000203 mixture Substances 0.000 claims description 2
- 230000000694 effects Effects 0.000 description 12
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 12
- 239000002245 particle Substances 0.000 description 10
- 239000002893 slag Substances 0.000 description 8
- 239000002002 slurry Substances 0.000 description 8
- WSFSSNUMVMOOMR-UHFFFAOYSA-N Formaldehyde Chemical compound O=C WSFSSNUMVMOOMR-UHFFFAOYSA-N 0.000 description 6
- 239000007787 solid Substances 0.000 description 6
- 238000000034 method Methods 0.000 description 5
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 description 4
- BWHMMNNQKKPAPP-UHFFFAOYSA-L potassium carbonate Chemical compound [K+].[K+].[O-]C([O-])=O BWHMMNNQKKPAPP-UHFFFAOYSA-L 0.000 description 4
- 239000004480 active ingredient Substances 0.000 description 3
- 229910052602 gypsum Inorganic materials 0.000 description 3
- 239000010440 gypsum Substances 0.000 description 3
- 238000002156 mixing Methods 0.000 description 3
- 239000000843 powder Substances 0.000 description 3
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
- 239000011398 Portland cement Substances 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 description 2
- 230000003247 decreasing effect Effects 0.000 description 2
- 150000002500 ions Chemical class 0.000 description 2
- PSZYNBSKGUBXEH-UHFFFAOYSA-M naphthalene-1-sulfonate Chemical compound C1=CC=C2C(S(=O)(=O)[O-])=CC=CC2=C1 PSZYNBSKGUBXEH-UHFFFAOYSA-M 0.000 description 2
- 239000008239 natural water Substances 0.000 description 2
- 229910000027 potassium carbonate Inorganic materials 0.000 description 2
- 235000011181 potassium carbonates Nutrition 0.000 description 2
- 238000010998 test method Methods 0.000 description 2
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 1
- KCXVZYZYPLLWCC-UHFFFAOYSA-N EDTA Chemical compound OC(=O)CN(CC(O)=O)CCN(CC(O)=O)CC(O)=O KCXVZYZYPLLWCC-UHFFFAOYSA-N 0.000 description 1
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 1
- JLVVSXFLKOJNIY-UHFFFAOYSA-N Magnesium ion Chemical compound [Mg+2] JLVVSXFLKOJNIY-UHFFFAOYSA-N 0.000 description 1
- 229920000877 Melamine resin Polymers 0.000 description 1
- UFWIBTONFRDIAS-UHFFFAOYSA-N Naphthalene Chemical compound C1=CC=CC2=CC=CC=C21 UFWIBTONFRDIAS-UHFFFAOYSA-N 0.000 description 1
- 229920002125 Sokalan® Polymers 0.000 description 1
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 239000011575 calcium Substances 0.000 description 1
- 229910001424 calcium ion Inorganic materials 0.000 description 1
- OSGAYBCDTDRGGQ-UHFFFAOYSA-L calcium sulfate Chemical compound [Ca+2].[O-]S([O-])(=O)=O OSGAYBCDTDRGGQ-UHFFFAOYSA-L 0.000 description 1
- ZOMBKNNSYQHRCA-UHFFFAOYSA-J calcium sulfate hemihydrate Chemical compound O.[Ca+2].[Ca+2].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O ZOMBKNNSYQHRCA-UHFFFAOYSA-J 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 229910002092 carbon dioxide Inorganic materials 0.000 description 1
- 239000004927 clay Substances 0.000 description 1
- 239000011162 core material Substances 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 239000010419 fine particle Substances 0.000 description 1
- 239000010881 fly ash Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- GPRLSGONYQIRFK-UHFFFAOYSA-N hydron Chemical compound [H+] GPRLSGONYQIRFK-UHFFFAOYSA-N 0.000 description 1
- 229910001425 magnesium ion Inorganic materials 0.000 description 1
- JDSHMPZPIAZGSV-UHFFFAOYSA-N melamine Chemical compound NC1=NC(N)=NC(N)=N1 JDSHMPZPIAZGSV-UHFFFAOYSA-N 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 239000004584 polyacrylic acid Substances 0.000 description 1
- 229910000028 potassium bicarbonate Inorganic materials 0.000 description 1
- 235000015497 potassium bicarbonate Nutrition 0.000 description 1
- 239000011736 potassium bicarbonate Substances 0.000 description 1
- TYJJADVDDVDEDZ-UHFFFAOYSA-M potassium hydrogencarbonate Chemical compound [K+].OC([O-])=O TYJJADVDDVDEDZ-UHFFFAOYSA-M 0.000 description 1
- 229940086066 potassium hydrogencarbonate Drugs 0.000 description 1
- 230000001603 reducing effect Effects 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 229910052708 sodium Inorganic materials 0.000 description 1
- 239000011734 sodium Substances 0.000 description 1
- 229910000029 sodium carbonate Inorganic materials 0.000 description 1
- 235000017550 sodium carbonate Nutrition 0.000 description 1
- 229910001415 sodium ion Inorganic materials 0.000 description 1
- BDHFUVZGWQCTTF-UHFFFAOYSA-M sulfonate Chemical compound [O-]S(=O)=O BDHFUVZGWQCTTF-UHFFFAOYSA-M 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
Landscapes
- Consolidation Of Soil By Introduction Of Solidifying Substances Into Soil (AREA)
- Investigating Or Analyzing Materials By The Use Of Electric Means (AREA)
Description
本発明は、改良土の製造方法に関する。 The present invention relates to a method for producing improved soil.
従来、土壌の強度を高める方法として、土壌にセメント系水硬性材料を添加して改良土を製造する方法が知られている。
ここで、改良土内に芯材を建て込む際や、改良土の一部を排泥として処理する際等には、作業性の観点から改良土の粘度は低いことが望まれるが、土壌に細粒分が多く含まれていると、土粒子及びセメントが凝集して粘度が高くなり、取り扱い難いものとなることがある。
このような観点から、改良土の分散性を高めて改良土の粘度を低下させるべく、セメント系水硬性材料とともに、分散剤が用いられている。
また、特に、土壌として、粘性が高い粘性土を用いる場合のように、より一層改良土の粘度を低下させることが求められる場合には、分散剤に加えて、分散助剤が用いられている（例えば、特許文献１、２）。
Conventionally, as a method for increasing the strength of soil, a method of adding a cement-based hydraulic material to soil to produce improved soil has been known.
Here, when building a core material in the improved soil, or when treating a part of the improved soil as waste mud, it is desirable that the viscosity of the improved soil is low from the viewpoint of workability, but the soil should have a low viscosity. If a large amount of fine particles are contained, soil particles and cement may aggregate to increase the viscosity, making it difficult to handle.
From this point of view, a dispersant is used together with the cement-based hydraulic material in order to increase the dispersibility of the improved soil and reduce the viscosity of the improved soil.
Further, in particular, when it is required to further reduce the viscosity of the improved soil, such as when a highly viscous soil is used as the soil, a dispersion aid is used in addition to the dispersant. (For example, Patent Documents 1 and 2).
ところで、分散剤及び分散助剤を使用する場合には、分散剤及び分散助剤を過剰量に使用すると、コストがかかるという問題があり、また、特に分散助剤については、過剰量を使用すると改良土の物性の変状を招くおそれがある。
そこで、従来は、分散剤及び分散助剤の配合量を決定するために、分散剤及び分散助剤の配合量を異ならせて、改良土の粘度を測定する配合試験が行われている。
しかし、このような配合試験には手間や時間を要していた。
By the way, when a dispersant and a dispersion aid are used, there is a problem that it is costly to use the dispersant and the dispersion aid in an excessive amount, and especially for a dispersion aid, if an excess amount is used. It may cause deterioration of the physical properties of the improved soil.
Therefore, conventionally, in order to determine the blending amounts of the dispersant and the dispersion aid, a blending test has been conducted in which the blending amounts of the dispersant and the dispersion aid are different and the viscosity of the improved soil is measured.
However, such a combination test requires labor and time.
そこで、本発明では、上記要望点に鑑み、分散助剤に着目し、添加量を抑制しつつ改良土の分散効果を発揮しやすい、分散助剤の量を簡便に把握しうる、改良土の製造方法を提供することを課題とする。 Therefore, in view of the above requirements, the present invention focuses on the dispersion aid, and can easily grasp the amount of the dispersion aid, which can easily exert the dispersion effect of the improved soil while suppressing the addition amount of the improved soil. An object is to provide a manufacturing method.
本発明に係る改良土の製造方法は、土壌と、セメント系水硬性材料と、分散剤と、分散助剤とが混合された改良土を作製する、改良土の製造方法であって、
前記分散助剤として、二価の陽イオンと錯体を形成できる錯体形成剤を含む分散助剤を用い、
前記土壌から採取した試料と、前記セメント系水硬性材料と、前記分散助剤とが混合された試験対象物の電気伝導率を測定する測定工程を前記改良土の作製前に実施し、
前記測定工程では、前記錯体形成剤の含有割合が異なる複数の試験対象物の電気伝導率を測定する。
The method for producing improved soil according to the present invention is a method for producing improved soil in which soil, a cement-based hydraulic material, a dispersant, and a dispersion aid are mixed.
As the dispersion aid, a dispersion aid containing a complex-forming agent capable of forming a complex with a divalent cation is used.
A measurement step of measuring the electric conductivity of the test object in which the sample collected from the soil, the cement-based hydraulic material, and the dispersion aid was mixed was carried out before the preparation of the improved soil.
In the measurement step, the electric conductivity of a plurality of test objects having different content ratios of the complex forming agent is measured.
本発明者が鋭意検討したところ、分散助剤が少なすぎると改良土の分散効果が発揮し難く、また、分散助剤が多すぎても増えた分による改良土の分散効果が乏しいことを見出した。
また、本発明者が鋭意検討したところ、前記測定工程で得られたデータをもとに、前記錯体形成剤の含有割合をｘ軸とし、前記試験対象物の電気伝導率をｙ軸としたグラフを作成すると、変曲点が見られ、また、前記錯体形成剤の濃度は、変曲点を境にして、改良土の分散を抑制する効果が大きく変わることを見出した。
また、電気伝導率は、測定が比較的簡便な指標である。
すなわち、斯かる改良土の製造方法によれば、前記変曲点を求めることにより、添加量を抑制しつつ改良土の分散効果を発揮しやすい、分散助剤の量を簡便に把握しうる。
As a result of diligent studies by the present inventor, it was found that if the amount of the dispersion aid is too small, the dispersion effect of the improved soil is difficult to be exhibited, and if the amount of the dispersion aid is too large, the dispersion effect of the improved soil due to the increase is poor. It was.
Further, as a result of diligent studies by the present inventor, a graph in which the content ratio of the complex-forming agent is on the x-axis and the electrical conductivity of the test object is on the y-axis based on the data obtained in the measurement step. It was found that inflection points were observed, and that the concentration of the complex-forming agent greatly changed the effect of suppressing the dispersion of the improved soil at the inflection points.
In addition, electrical conductivity is an index that is relatively easy to measure.
That is, according to such a method for producing improved soil, by obtaining the inflection point, it is possible to easily grasp the amount of the dispersion aid, which is likely to exert the dispersion effect of the improved soil while suppressing the addition amount.
ここで、本発明に係る改良土の製造方法の一態様では、前記分散助剤は、前記錯体形成剤として、アルカリ金属の炭酸塩及びアルカリ金属の重炭酸塩の少なくとも一方を含有する。 Here, in one aspect of the method for producing improved soil according to the present invention, the dispersion aid contains at least one of an alkali metal carbonate and an alkali metal bicarbonate as the complex-forming agent.
また、前記分散助剤は、前記錯体形成剤として、アルカリ金属の炭酸塩及びアルカリ金属の重炭酸塩の少なくとも一方を含有する改良土の製造方法の一態様では、前記分散助剤は、前記錯体形成剤として、炭酸水素ナトリウムを含有する。 Further, in one aspect of the method for producing improved soil, in which the dispersion aid contains at least one of an alkali metal carbonate and an alkali metal bicarbonate as the complex-forming agent, the dispersion aid is the complex. It contains sodium hydrogen carbonate as a forming agent.
また、本発明に係る改良土の製造方法の他態様では、前記土壌が粘性土である。 Further, in another aspect of the method for producing improved soil according to the present invention, the soil is cohesive soil.
以上のように、本発明によれば、添加量を抑制しつつ改良土の分散効果を発揮しやすい、分散助剤の量を簡便に把握しうる。 As described above, according to the present invention, it is possible to easily grasp the amount of the dispersion aid, which tends to exert the dispersion effect of the improved soil while suppressing the addition amount.
以下、添付図面を参照しつつ、本発明の一実施形態について説明する。 Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.
本実施形態に係る改良土の製造方法は、土壌と、セメント系水硬性材料と、分散剤と、分散助剤とが混合された改良土を作製する、改良土の製造方法である。 The method for producing improved soil according to the present embodiment is a method for producing improved soil in which soil, a cement-based hydraulic material, a dispersant, and a dispersion aid are mixed.
前記セメント系水硬性材料は、セメントを含有する。 The cement-based hydraulic material contains cement.
前記セメントとしては、例えば、普通、早強、超早強、白色、耐硫酸塩、中庸熱、低熱などの各種ポルトランドセメント、該ポルトランドセメントに高炉スラグ、フライアッシュ、シリカ等を混合してなる混合セメント、アルミナセメントなどの特殊セメントなどが挙げられる。
前記セメントは、高炉スラグ、石膏を含有してもよい。また、前記セメント系水硬性材料は、硬化促進剤などの混和剤を含有してもよい。
Examples of the cement include various Portland cements such as ordinary, early-strength, ultra-fast-strength, white, sulfate-resistant, moderate heat, and low heat, and a mixture of the Portland cement mixed with blast furnace slag, fly ash, silica, and the like. Examples thereof include special cements such as cement and alumina cement.
The cement may contain blast furnace slag and gypsum. Further, the cement-based hydraulic material may contain an admixture such as a curing accelerator.
前記石膏としては、無水石膏（ＣａＳＯ4 ）、半水石膏（ＣａＳＯ4 ・０．５Ｈ2 Ｏ）、二水石膏（ＣａＳＯ4 ・２Ｈ2 Ｏ）等が挙げられる。 As the gypsum, anhydrous gypsum (CaSO 4), hemihydrate gypsum (CaSO 4 · 0.5H 2 O) , gypsum (CaSO 4 · 2H 2 O), and the like.
前記高炉スラグとしては、高炉水砕スラグ等が挙げられ、該高炉水砕スラグとしては、高炉水砕スラグの微粉末等が挙げられる。
高炉水砕スラグの微粉末としては、ＪＩＳ Ａ６２０６：２０１３の“高炉スラグ微粉末”が好ましく、すなわち、比表面積が２，７５０ｃｍ２／ｇ以上１０，０００ｃｍ２／ｇ未満のものが好ましい。なお、比表面積は、ＪＩＳ Ｒ５２０１：２０１５の比表面積試験に従って測定することができる。
Examples of the blast furnace slag include blast furnace granulated slag, and examples of the blast furnace granulated slag include fine powder of blast furnace granulated slag.
As the fine powder of the blast furnace granulated slag, JIS A6206: 2013 "blast furnace slag fine powder" is preferable, that is, a specific surface area of 2,750 cm 2 / g or more and less than 10,000 cm 2 / g is preferable. The specific surface area can be measured according to the specific surface area test of JIS R5201: 2015.
前記分散剤としては、例えば、ナフタレンスルホン酸塩のホルマリン縮合物、メラミンスルホン酸塩のホルマリン縮合物、ポリカルボン酸、ポリアクリル酸などが挙げられる。 Examples of the dispersant include a formalin condensate of naphthalene sulfonate, a formalin condensate of melamine sulfonate, a polycarboxylic acid, and a polyacrylic acid.
前記分散助剤としては、二価の陽イオンと錯体を形成できる錯体形成剤を含む分散助剤を用いることが重要である。
前記錯体形成剤としては、アルカリ金属の炭酸塩、アルカリ金属の重炭酸塩、エチレンジアミン四酢酸などが挙げられる。
前記アルカリ金属の炭酸塩としては、炭酸ナトリウム、炭酸カリウム、炭酸ナトリウムカリウムなどが挙げられる。
前記アルカリ金属の重炭酸塩としては、炭酸水素ナトリウム、炭酸水素カリウムなどが挙げられる。
As the dispersion aid, it is important to use a dispersion aid containing a complex-forming agent capable of forming a complex with a divalent cation.
Examples of the complex forming agent include alkali metal carbonates, alkali metal bicarbonates, ethylenediaminetetraacetic acid and the like.
Examples of the alkali metal carbonate include sodium carbonate, potassium carbonate, potassium carbonate and the like.
Examples of the alkali metal bicarbonate include sodium hydrogencarbonate and potassium hydrogencarbonate.
さらに、本実施形態に係る改良土の製造方法では、前記土壌から採取した試料と、前記セメント系水硬性材料と、前記分散助剤とが混合された試験対象物の電気伝導率を測定する測定工程を前記改良土の作製前に実施する。
前記測定工程では、前記錯体形成剤の含有割合が異なる複数の試験対象物の電気伝導率を測定する。
Further, in the method for producing improved soil according to the present embodiment, measurement for measuring the electric conductivity of a test object in which a sample collected from the soil, the cement-based hydraulic material, and the dispersion aid is mixed is measured. The step is carried out before the preparation of the improved soil.
In the measurement step, the electric conductivity of a plurality of test objects having different content ratios of the complex forming agent is measured.
前記土壌としては、粘性土が挙げられる。
本実施形態における粘性土は、地盤工学基準「地盤材料の工学的分類方法」（ＪＧＳ００５１−２０００）において、土質材料を１００質量％とした際に、粘土及びシルトを合わせて５０質量％以上含む土を意味し、言いかえれば、土質材料を１００質量％とした際に、粒径０．００７５ｍｍ未満の粒子を５０質量％以上含む土を意味する。
土質材料を１００質量％とした際の、粒径０．００７５ｍｍ未満の粒子の割合は、ＪＩＳ Ａ１２０４：２００９「土の粒度試験方法」によって測定することができる。
Examples of the soil include cohesive soil.
The cohesive soil in this embodiment is a soil containing 50% by mass or more of clay and silt in total when the soil material is 100% by mass in the ground engineering standard "Engineering classification method of ground material" (JGS0051-2000). In other words, when the soil material is 100% by mass, it means soil containing 50% by mass or more of particles having a particle size of less than 0.0075 mm.
The proportion of particles having a particle size of less than 0.0075 mm when the soil material is 100% by mass can be measured by JIS A 1204: 2009 “Soil particle size test method”.
前記改良土は、上述したセメント系水硬性材料に加えて、水も含有する。 The improved soil contains water in addition to the cement-based hydraulic material described above.
前記改良土では、湿潤状態の土壌１ｍ３当たりのセメント系水硬性材料の量が、好ましくは１００〜１０００ｋｇ／ｍ３、より好ましくは２００〜５００ｋｇ／ｍ３である。
また、前記改良土は、前記セメント系水硬性材料１００質量部に対して、水を、好ましくは４５〜２００質量部、より好ましくは６０〜１３０質量部含有する。
In the improved soil, the amount of the cement-based hydraulic material per 1 m 3 of the wet soil is preferably 100 to 1000 kg / m 3 , and more preferably 200 to 500 kg / m 3 .
Further, the improved soil contains water, preferably 45 to 200 parts by mass, more preferably 60 to 130 parts by mass, with respect to 100 parts by mass of the cement-based hydraulic material.
本実施形態に係る改良土の製造方法は、上記のように構成されているので、以下の利点を有するものである。 Since the method for producing improved soil according to the present embodiment is configured as described above, it has the following advantages.
なお、本発明に係る改良土の製造方法は、上記実施形態に限定されるものではない。また、本発明に係る改良土の製造方法は、上記した作用効果に限定されるものでもない。本発明に係る改良土の製造方法は、本発明の要旨を逸脱しない範囲で種々の変更が可能である。 The method for producing the improved soil according to the present invention is not limited to the above embodiment. Further, the method for producing improved soil according to the present invention is not limited to the above-mentioned effects. The method for producing improved soil according to the present invention can be variously changed without departing from the gist of the present invention.
次に、試験例を挙げて本発明についてさらに具体的に説明する。 Next, the present invention will be described in more detail with reference to test examples.
（試験例１）
＜土壌試料＞
使用した土壌試料を表１に示す。なお、自然含水比は、「土中の水の質量／土中の固形分の質量」を「質量％」で表したものを意味する。自然含水比は、地盤工学会のＪＧＳ０１２１−２００９「土の含水比試験方法」により測定した。
(Test Example 1)
<Soil sample>
The soil samples used are shown in Table 1. The natural water content ratio means "mass of water in soil / mass of solids in soil" expressed in "mass%". The natural water content was measured by JGS0121-2009 "Soil Water Content Test Method" of the Japanese Geotechnical Society.
＜使用材料＞
以下に示すセメント系水硬性材料、及び、分散助剤を用いた。
セメント系水硬性材料：市販のセメント系水硬性材料
分散助剤たる錯体形成剤：炭酸水素ナトリウム（ＮａＨＣＯ３）
<Material used>
The cement-based hydraulic materials and dispersion aids shown below were used.
Cement-based hydraulic material: Commercially available cement-based hydraulic material Complex-forming agent that is a dispersion aid: Sodium hydrogen carbonate (NaHCO 3 )
セメント系水硬性材料、炭酸水素ナトリウム、及び、水を混合してスラリーを作製した。次に、該スラリーと上記土壌試料とを混合して試験対象物を作製した。そして、該試験対象物の電気伝導率を測定した。
ここで、セメント系水硬性材料は、湿潤状態の土壌試料１Ｌに対して３１０ｇとなるようにした。
また、炭酸水素ナトリウムは、図１〜４に示す範囲で添加した。なお、図における「ＮａＨＣＯ３添加量（Ｃ×％）」は、「炭酸水素ナトリウムの質量／セメント系水硬性材料の質量」を「質量％」で表したものを意味する。
さらに、水は、試験対象物の固形分の質量（土壌試料の乾燥質量と、セメント系水硬性材料の質量と、炭酸水素ナトリウムの質量との合計の質量）に対して１０倍の質量となるようにした。
A cement-based hydraulic material, sodium hydrogen carbonate, and water were mixed to prepare a slurry. Next, the slurry and the soil sample were mixed to prepare a test object. Then, the electric conductivity of the test object was measured.
Here, the amount of the cement-based hydraulic material was adjusted to 310 g with respect to 1 L of the wet soil sample.
In addition, sodium hydrogen carbonate was added in the range shown in FIGS. 1 to 4. In addition, "NaHCO 3 addition amount (C ×%)" in the figure means "mass of sodium hydrogen carbonate / mass of cement-based hydraulic material" expressed by "mass%".
Furthermore, the mass of water is 10 times the mass of the solid content of the test object (the total mass of the dry mass of the soil sample, the mass of the cement-based hydrohard material, and the mass of sodium hydrogen carbonate). I did it.
粘性土１〜４における結果をそれぞれ図１〜４に示す。 The results of the cohesive soils 1 to 4 are shown in FIGS. 1 to 4, respectively.
図１〜４に示すように、前記炭酸水素ナトリウムの含有割合をｘ軸とし、前記試験対象物の電気伝導率をｙ軸としたグラフを作成すると、変曲点が見られた。また、前記炭酸水素ナトリウムは、変曲点以下の量では、量が増えても、電気伝導率があまり変化しなかったが、変曲点を超えた量では、量が増えるに従って、電気伝導率が高くなった。 As shown in FIGS. 1 to 4, when a graph was created in which the content ratio of the sodium hydrogen carbonate was on the x-axis and the electrical conductivity of the test object was on the y-axis, inflection points were observed. Further, the electric conductivity of the sodium hydrogen carbonate did not change so much even if the amount increased below the inflection point, but when the amount exceeded the inflection point, the electric conductivity increased as the amount increased. Has become higher.
（試験例２）
試験例１に示す粘性土１、セメント系水硬性材料、及び、分散助剤たる錯体形成剤を用いた。
さらに、以下に示す分散剤を用いた。
分散剤：ナフタレンスルホン酸塩のホルマリン縮合物（マイティ １５０、花王社製）
(Test Example 2)
The cohesive soil 1 shown in Test Example 1, the cement-based hydraulic material, and the complex-forming agent as a dispersion aid were used.
Furthermore, the following dispersants were used.
Dispersant: Formalin condensate of naphthalene sulfonate (Mighty 150, manufactured by Kao Corporation)
セメント系水硬性材料、分散剤、錯体形成剤たる炭酸水素ナトリウム、及び、水を混合してスラリーを作製した。次に、該スラリーと土壌試料とを混合して改良土を作製した。そして、該改良土の粘度を測定した。
ここで、湿潤状態の土壌試料１Ｌに対して、セメント系水硬性材料を３１０ｇ、水を２４８ｇ、炭酸水素ナトリウムを０．０ｇ、１２．９ｇ又は１３．３ｇ、分散剤を１２．９ｇとなるようにした。
粘度については、回転粘度計（ビスコテスタ ＶＴ−０６、リオン社製）を使用して粘度を測定した。
A cement-based hydraulic material, a dispersant, sodium hydrogen carbonate as a complex-forming agent, and water were mixed to prepare a slurry. Next, the slurry and a soil sample were mixed to prepare improved soil. Then, the viscosity of the improved soil was measured.
Here, the amount of the cement-based hydraulic material is 310 g, the amount of water is 248 g, the amount of sodium hydrogen carbonate is 0.0 g, 12.9 g or 13.3 g, and the amount of the dispersant is 12.9 g with respect to 1 L of the wet soil sample. I made it.
Regarding the viscosity, the viscosity was measured using a rotational viscometer (Viscometer VT-06, manufactured by Rion Co., Ltd.).
結果を図５に示す。 The results are shown in FIG.
図５に示すように、炭酸水素ナトリウムの含有量は、図１に示された変曲点（Ｃ×４．１％）を境にして、粘度が大幅に低くなることが分かった。
すなわち、炭酸水素ナトリウムの含有量は、図１に示された変曲点（Ｃ×４．１％）を境にして、改良土の分散を抑制する効果が大きく変わることがわかった。
よって、炭酸水素ナトリウムの含有量を変曲点の量にすることで、添加量を抑制しつつ改良土の分散効果を発揮させることができる。
As shown in FIG. 5, it was found that the viscosity of the sodium hydrogen carbonate content was significantly reduced at the inflection point (C × 4.1%) shown in FIG.
That is, it was found that the content of sodium hydrogen carbonate greatly changes the effect of suppressing the dispersion of the improved soil at the inflection point (C × 4.1%) shown in FIG.
Therefore, by setting the content of sodium hydrogen carbonate to the amount of the inflection point, it is possible to exert the effect of dispersing the improved soil while suppressing the addition amount.
このような結果が得られたのは以下の理由によるものと考えられる。
土粒子は、通常、表面が負の電荷を帯びており、一方で、セメント系水硬性材料や土壌には、カルシウムイオンやマグネシウムイオンなどの二価の陽イオンが含まれている。
そして、改良土においては、土粒子は、二価の陽イオンを含めた陽イオンと反応することによって凝集される。
しかし、炭酸水素ナトリウムの炭酸イオンが改良土に含まれると、炭酸イオンが二価の陽イオンと錯体を形成し、不溶化する。
炭酸水素ナトリウムの含有量が変曲点以下の領域では、炭酸イオンが二価の陽イオンと結合し、二価の陽イオンが減少するが、それとともに、炭酸水素ナトリウムに含まれる水素イオンとナトリウムイオンが放出されるので、炭酸水素ナトリウムの含有量を増やしても電気伝導率はほとんど変化しないと考えられる。また、炭酸水素ナトリウムの含有量が変曲点を超える領域では、改良土に存在する二価の陽イオンの多くが炭酸イオンと十分に結合した状態となる一方で、炭酸水素ナトリウムに含まれる炭酸イオン、水素イオン、ナトリウムイオンが放出されるので、炭酸水素ナトリウムの含有量が増えると、電気伝導率が高くなると考えられる。
すなわち、炭酸水素ナトリウムに限らず、二価の陽イオンと錯体を形成できる錯体形成剤の含有量を変曲点の量付近にすることで、添加量を抑制しつつ改良土の分散効果を発揮させることができると考えられる。
It is considered that such a result was obtained for the following reasons.
The surface of soil particles is usually negatively charged, while cement-based hydrohard materials and soil contain divalent cations such as calcium and magnesium ions.
Then, in the improved soil, the soil particles are aggregated by reacting with cations including divalent cations.
However, when the carbonate ion of sodium hydrogen carbonate is contained in the modified soil, the carbonate ion forms a complex with a divalent cation and is insolubilized.
In the region where the content of sodium hydrogen carbonate is below the turning point, the carbonate ion binds to the divalent cation and the divalent cation decreases, but at the same time, the hydrogen ion and sodium contained in the sodium hydrogen carbonate Since ions are released, it is considered that the electrical conductivity hardly changes even if the content of sodium hydrogen carbonate is increased. Further, in the region where the content of sodium hydrogen carbonate exceeds the turning point, most of the divalent cations present in the improved soil are in a state of being sufficiently bonded to the carbonate ion, while the carbon dioxide contained in the sodium hydrogen carbonate is contained. Since ions, hydrogen ions, and sodium ions are released, it is considered that the electrical conductivity increases as the content of sodium hydrogen carbonate increases.
That is, by setting the content of the complex forming agent capable of forming a complex with divalent cations, not limited to sodium hydrogen carbonate, to the vicinity of the amount of the inflection point, the effect of dispersing the improved soil is exhibited while suppressing the addition amount. It is thought that it can be made to.
（試験例３）
セメント系水硬性材料、分散剤、及び、水を混合してスラリーを作製した（後述する図６の「分散剤のみ」）。次に、該スラリーと土壌試料とを混合して改良土を作製した。そして、該改良土の粘度を測定した。なお、粘度は試験例２と同様な方法で測定した。
セメント系水硬性材料、分散剤、及び、土壌試料は、試験例２で用いたものと同じものを用いた。
ここで、湿潤状態の土壌試料１Ｌに対して、セメント系水硬性材料を３１０ｇ、水を２４８ｇとなるようにした。
また、分散剤は、図６に示す範囲で添加した。なお、図における「有効成分量（土粒子×％）」は、「分散剤の固形分の質量／土壌試料の固形分（乾燥した土壌試料）の質量」を「質量％」で表したものを意味する。
(Test Example 3)
A cement-based hydraulic material, a dispersant, and water were mixed to prepare a slurry (“dispersant only” in FIG. 6 described later). Next, the slurry and a soil sample were mixed to prepare improved soil. Then, the viscosity of the improved soil was measured. The viscosity was measured by the same method as in Test Example 2.
The cement-based hydraulic material, dispersant, and soil sample used were the same as those used in Test Example 2.
Here, the amount of the cement-based hydraulic material was 310 g and the amount of water was 248 g with respect to 1 L of the wet soil sample.
The dispersant was added in the range shown in FIG. The "active ingredient amount (soil particles x%)" in the figure is the "mass of the solid content of the dispersant / the mass of the solid content of the soil sample (dry soil sample)" expressed in "mass%". means.
また、セメント系水硬性材料と、分散助剤（炭酸水素ナトリウム）及び分散剤が混合された混和剤（混合品）と、水とを混合してスラリーを作製した（図６の「混合品」）。次に、該スラリーと土壌試料とを混合して改良土を作製した。そして、該改良土の粘度を測定した。なお、粘度は試験例２と同様な方法で測定した。
セメント系水硬性材料、及び、土壌試料は、試験例２で用いたものと同じものを用いた。
ここで、湿潤状態の土壌試料１Ｌに対して、セメント系水硬性材料を３１０ｇ、水を２４８ｇとなるようにした。
また、混和剤は、図６に示す範囲で添加した。なお、図における「有効成分量（土粒子×％）」は、「混合品の固形分の質量／土壌試料の固形分（乾燥した土壌試料）の質量」を「質量％」で表したものを意味する。
Further, a cement-based hydraulic material, an admixture (mixed product) in which a dispersion aid (sodium hydrogen carbonate) and a dispersant were mixed, and water were mixed to prepare a slurry (“mixed product” in FIG. 6). ). Next, the slurry and a soil sample were mixed to prepare improved soil. Then, the viscosity of the improved soil was measured. The viscosity was measured by the same method as in Test Example 2.
The cement-based hydraulic material and soil sample used were the same as those used in Test Example 2.
Here, the amount of the cement-based hydraulic material was 310 g and the amount of water was 248 g with respect to 1 L of the wet soil sample.
The admixture was added in the range shown in FIG. The "active ingredient amount (soil particles x%)" in the figure is the "mass of the solid content of the mixed product / the mass of the solid content of the soil sample (dry soil sample)" expressed in "mass%". means.
結果を図６に示す。 The results are shown in FIG.
図６に示すように、分散剤のみを用いた場合には、分散剤の量を増やすに従って徐々に改良土の粘度が低下した。
一方で、混合品を用いた場合には、混合品の量が、ある添加量を超えると急激に粘度が低下した。
また、粘度を十分に低減できた領域では、分散助剤たる炭酸水素ナトリウムを用いた方が、有効成分量が少なくても粘度低減効果が高かった。
As shown in FIG. 6, when only the dispersant was used, the viscosity of the improved soil gradually decreased as the amount of the dispersant was increased.
On the other hand, when a mixed product was used, the viscosity sharply decreased when the amount of the mixed product exceeded a certain amount.
Further, in the region where the viscosity could be sufficiently reduced, the use of sodium hydrogen carbonate as a dispersion aid had a higher viscosity reducing effect even if the amount of the active ingredient was small.
以上より、二価の陽イオンと錯体を形成できる錯体形成剤たる分散助剤の量を、添加量を抑制しつつ改良土の分散効果を発揮しやすい量にすれば、分散剤及び分散助剤の総量が小さくても、改良土の分散効果を発揮しやすくなる。 Based on the above, if the amount of the dispersion aid, which is a complex-forming agent capable of forming a complex with divalent cations, is set to an amount that facilitates the dispersion effect of the improved soil while suppressing the addition amount, the dispersant and the dispersion aid Even if the total amount of the soil is small, the effect of dispersing the improved soil can be easily exerted.
Claims (4)
前記分散助剤として、二価の陽イオンと錯体を形成できる錯体形成剤を含む分散助剤を用い、
前記土壌から採取した試料と、前記セメント系水硬性材料と、前記分散助剤とが混合された試験対象物の電気伝導率を測定する測定工程を前記改良土の作製前に実施し、
前記測定工程では、前記錯体形成剤の含有割合が異なる複数の試験対象物の電気伝導率を測定する、改良土の製造方法。 A method for producing improved soil, which is a mixture of soil, a cement-based hydraulic material, a dispersant, and a dispersion aid.
As the dispersion aid, a dispersion aid containing a complex-forming agent capable of forming a complex with a divalent cation is used.
A measurement step of measuring the electric conductivity of the test object in which the sample collected from the soil, the cement-based hydraulic material, and the dispersion aid was mixed was carried out before the preparation of the improved soil.
In the measuring step, a method for producing improved soil, which measures the electric conductivity of a plurality of test objects having different content ratios of the complex forming agent.
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