JP2006328320A - Agent for treating water-containing soil, and method for granulating water-containing soil - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an agent for treating water-containing soil, capable of corresponding even to the water-containing soil with high water content by a small amount; and to provide a method for granulating the water-containing soil. <P>SOLUTION: The agent for treating the water-containing soil contains (a) a water-soluble polymer containing a carboxy group (including a carboxylic acid salt group) and a sulfonic acid group (including a sulfonic acid salt group) regulated so that the content of a sulfonic acid group-containing unit may be 0.5-50 mol% based on 100 mol% whole constituent units, and (b) a smectite clay as constituent elements. The method for granulating the water-containing soil involves mixing the agent for treating the water-containing soil with the water-containing soil. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to a treatment agent and a treatment method for modifying hydrous soil so that it can be reused as a backfill material as an alternative to sand and the like. The treatment agent and granulation method of the present invention can be applied to hydrous soil having a high moisture content and extremely low viscosity.

  Of the soil generated during construction work, the soil generated during excavation work may cause water to flow into the excavation part and be discharged to the outside as sludge. Since such sludge has a high water content, it remains as it is. However, it cannot be transported by ordinary trucks and dump trucks, and naturally it cannot be used as a backfill material. For this reason, it has been performed that the mud can be transported by subjecting it to a dehydration process or a solidification process.

  However, even if dehydration treatment is performed, it is necessary to make further appropriate improvements in order to recycle as described above. In the case of solidification treatment, what should be done with the obtained solidified soil? However, there was a problem that there were not so many places to dispose of solidified soil to match the amount of mud generated.

  From such a point of view, studies have been made on the use of hydrous soil such as mud in the form of a smooth sandy granular material for backfilling. As a granulation method, for example, there is a method in which a carboxyl group-containing water-soluble polymer powder is added and mixed, then lime is added and mixed, and granulated through curing (Patent Document 1). In addition, as a technique for solving the problem that the carboxyl group-containing water-soluble polymer powder is difficult to dissolve in water-containing soil, there is a method of granulating using a water-soluble polymer containing a carboxyl group and a sulfone group (patent document) 2). Furthermore, Patent Document 3 discloses a method in which a copolymer of acrylamide and acrylic acid and sodium alginate are mixed with mud and granulated. In addition, Patent Document 4 proposes a water-containing soil solidifying agent containing a water-soluble polymer compound having a water thickening property, a phyllosilicate mineral, and a surfactant used as necessary.

Each of the above prior arts has its own characteristics and exhibits its effect, but it may not be said that it has sufficient treatment performance to apply to mud with a high water content ratio and low viscosity, For example, a large amount of a treatment agent such as the water-soluble polymer described above is often required.
JP-A-6-17052 JP 2000-136383 A Japanese Patent Laid-Open No. 10-152682 Japanese Patent Laid-Open No. 4-103689

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a hydrous soil treatment agent and a hydrous soil granulation method that can be made into a fine granular soil in a small amount even in a hydrous soil with a high water content. There is to do.

  The water-containing soil treatment agent of the present invention that can achieve the above-described object contains (a) a carboxyl group (including a carboxylate group) and a sulfone group (including a sulfonate group), and in 100 mol% of all the structural units, It has a gist in that the water-soluble polymer having a sulfone group-containing unit of 0.5 to 50 mol% and (b) smectite clay are included in the constituent elements.

Hereinafter, in the present specification, the “carboxyl group” in the above-mentioned (a) water-soluble polymer and the monomer for forming the polymer is a free carboxyl group (—COOH group) unless otherwise specified. In addition, a carboxylate group is also included, and the “sulfone group” includes a sulfonate group in addition to a free sulfone group (—SO ₃ H group) unless otherwise specified.

  The water-containing soil treatment agent is also a preferred embodiment of the present invention when (c) a hydraulic substance is a constituent element.

  The granulation method of the hydrous soil of the present invention is summarized in that the hydrous soil treatment agent of the present invention is mixed with the hydrous soil.

  In addition, (c) hydraulic substance, which is one of the components of the hydrous soil treatment agent, is added after (a) a water-soluble polymer and (b) smectite clay are mixed and dispersed in the hydrous soil. It is preferable to mix.

  Thus, the granulated method for hydrous soil of the present invention is a method for producing granular soil from hydrous soil, and the granular soil obtained by these granulated methods is also included in the present invention.

  The hydrous soil treatment agent of the present invention using a specific water-soluble polymer and smectite clay as essential constituents has excellent hydrous soil treatment performance, and is a hydrous soil with a high moisture content and extremely low viscosity. However, it is possible to obtain a granular soil that can be used as a substitute for sand, for example, in a short time with a small amount of use.

  Moreover, the granulated method of the hydrous soil of the present invention using the hydrous soil treatment agent can reuse the hydrous soil usually discarded as sludge, so that environmental conservation, resource saving, and life extension of the disposal site can be achieved. At the same time, it is possible to reduce the disposal cost of hydrous soil.

  Furthermore, the granular soil obtained by the treatment agent and the granulation method of the present invention can be transported by truck, and can be reused for various purposes such as a backfill material as a substitute for sand.

  In this technical field, for example, as disclosed in Patent Document 4 above, it is known that a phyllosilicate mineral can be used as a component of a hydrous soil treatment agent together with a water-soluble polymer.

  However, when the present inventors used smectite clay, which is a kind of phyllosilicate mineral, as a hydrous soil treatment agent together with a specific water-soluble polymer, the conventional hydrous soil treatment agent can be granulated. It was found that even if it is a water-containing soil having a high water content ratio and a low viscosity, it can be granulated with a very small amount, and the diameter of the granular soil after the treatment can be made fine, and the present invention has been completed. It was.

  That is, the water-containing soil treatment agent of the present invention includes (a) a water-soluble polymer containing a carboxyl group and a sulfone group, and having a sulfone group-containing unit of 0.5 to 50 mol% in 100 mol% of all the structural units; (B) It has the greatest feature in that it contains smectite clay as a constituent element.

  The mechanism of the hydrous soil treatment by the hydrous soil treatment agent of the present invention is considered as follows. (A) When the water-soluble polymer is added to and mixed with the water-containing soil, the water-soluble polymer is combined with water while being dissolved in water, so that these waters are taken in and contain such water. In the state (a) the molecular chain of the water-soluble polymer is adsorbed on some soil particles, and by adhering and bonding the soil particles to each other, (a) water is taken into the water-soluble polymer-soil particle network, In order to achieve granulation, in the case of soil with a high water content, (a) the water-soluble polymer alone has a weak force to bind soil particles, so the amount added to form a stable granulated state Need to be increased. However, by coexisting (b) smectite clay in a system where hydrous soil and (a) water-soluble polymer exist, (b) crosslinking of water-soluble polymer via (b) smectite clay Occurs, the apparent molecular weight increases and the cohesive force improves. Thereby, a stronger bond is formed between the soil particles, and the water in the hydrous soil is included in the gaps between the soil particles. In addition, (b) Smectite clay itself can take in a large amount of free water in hydrous soil because of its structural characteristics. Combined with these effects, a stable granulated product can be obtained from water-containing soil having a high water content ratio and low viscosity. Hereinafter, components of the hydrous soil treatment agent of the present invention will be described in detail.

  Examples of the carboxyl group-containing monomer that can be used in the synthesis of the water-soluble polymer (a) used in the present invention include (meth) acrylic acid, crotonic acid, vinyl acetic acid, maleic acid, itaconic acid, mesaconic acid, and fumaric acid. Acid, citraconic acid, N- (meth) acryloylaspartic acid, and carboxylates (for example, alkali metal salts and ammonium salts) of these monomers. These polymerizable monomers can be used alone or in combination of two or more. Among the above exemplified monomers, (meth) acrylic acid and its salt are preferable, and (meth) acrylic acid is more preferable.

  In addition, the water-soluble polymer (a) of the present invention contains not only a carboxyl group derived from the carboxyl group-containing monomer but also a sulfone group. For example, a carboxyl group-containing water-soluble polymer such as poly (meth) acrylic acid has a relatively slow dissolution rate in water, and a water-containing soil treatment using such a water-soluble polymer compares the treatment time of water-containing soil. May be longer. However, even in such a carboxyl group-containing water-soluble polymer, by further introducing a sulfone group or a sulfonate group, the dissolution rate in water becomes very high. Therefore, the water-containing soil treatment agent using the water-soluble polymer that also contains a sulfone group in addition to the carboxyl group enables water-containing soil treatment in a short time.

  In the water-soluble polymer (a) according to the present invention, the sulfone group-containing monomer that can be used for introducing a sulfone group is not particularly limited as long as it is a polymerizable monomer having a sulfone group. 2-acrylamido-2-methylpropanesulfonic acid, (meth) allylsulfonic acid, allyloxybenzenesulfonic acid, 2-hydroxy-3- (2-propenyloxy) propanesulfonic acid, isopropenylsulfonic acid, styrenesulfonic acid, vinyl Examples thereof include sulfonic acid, sulfoethyl (meth) acrylate, sulfonated products of isoprene, and sulfonates (alkali metal salts, ammonium salts, and the like) of these monomers. These monomers can be used alone or in combination of two or more. Among the monomers exemplified above, 2-acrylamido-2-methylpropanesulfonic acid, sulfoethyl (meth) acrylate, and salts thereof are preferable, and 2-acrylamido-2-methylpropanesulfonic acid and sulfoethyl (meth) acrylate are preferable. Particularly preferred. Therefore, (a) a water-soluble polymer is obtained by polymerizing a monomer composition containing (meth) acrylic acid and 2-acrylamido-2-methylpropanesulfonic acid and / or sulfoethyl (meth) acrylate. Are most preferred.

  (A) In the formation of the water-soluble polymer, other monomers copolymerizable with the above-mentioned carboxyl group-containing monomer or sulfone group-containing monomer may be used. Examples of such other monomers include monoethylenically unsaturated acids such as allyl phosphonic acid, isopropenyl phosphonic acid, vinyl phosphonic acid, and salts thereof; polyethylene glycol (meth) acrylate, methoxy polyethylene glycol ( Esters of polyalkylene glycols and the above carboxyl group-containing monomers such as (meth) acrylate; methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, hydroxyethyl (meth) (Meth) acrylic acid esters such as acrylate and hydroxypropyl (meth) acrylate; vinyl esters such as vinyl acetate, vinyl propionate, vinyl pivalate, vinyl benzoate and vinyl cinnamate; methyl vinyl ether, ethyl Alkyl vinyl ethers such as ruvinyl ether; allyl alcohol, methallyl alcohol, 3-methyl-3-buten-1-ol, 3-methyl-2-buten-1-ol, 2-methyl-3-buten-2-ol, etc. Unsaturated vinyl alcohols; aldehyde group-containing vinyl monomers such as acrolein; nitrile group-containing vinyl monomers such as (meth) acrylonitrile; amide monomers such as (meth) acrylamide and Nt-butylacrylamide; Ethyl methacrylate; styrene; ethylene oxide adduct of allyl alcohol; N-vinyl-2-pyrrolidone; N-vinylacetamide; N-vinylformamide: and the like.

  Among the other monomers exemplified above, monoethylenically unsaturated acid; ester of polyalkylene glycol and carboxyl group-containing monomer; (meth) acrylic acid ester; vinyl ester; alkyl vinyl ether; unsaturated alcohol; Gases such as ammonia may be generated during the treatment of hydrous soil such as phosphoethyl methacrylate; styrene; ethylene oxide adduct of allyl alcohol; N-vinyl-2-pyrrolidone; N-vinylacetamide; N-vinylformamide; No monomer is more preferred. These other monomers may use only 1 type as needed and may use 2 or more types together. Among the other monomers exemplified above, methyl (meth) acrylate, hydroxyethyl (meth) acrylate, and N-vinyl-2-pyrrolidone are particularly preferable.

  (A) In the water-soluble polymer, the carboxyl group-containing unit is 50 mol% or more, preferably 75 mol% or more, more preferably 80 mol% or more, out of 100 mol% of all the structural units of the water-soluble polymer. It is recommended that it be 5 mol% or less, preferably 99 mol% or less. When the carboxyl group-containing unit amount is below the above range, it may be necessary to increase the amount of the hydrous soil treatment agent used for the hydrous soil. On the other hand, when it exceeds the above range, it becomes easy to be affected by metal ions present in the soil, and the fluctuation range of the usage amount of the hydrous soil treatment agent may become large.

  In addition, in (a) the water-soluble polymer, in 100 mol% of all the structural units of the water-soluble polymer, the sulfone group-containing unit is 0.5 mol% or more, more preferably 1 mol% or more, and 50 mol% or less. More preferably, it is 25 mol% or less, More preferably, it is 20 mol% or less. If the amount of the sulfone group-containing unit is below the above range, the effect of improving the water dissolution rate of the polymer due to the introduction of the sulfone group may not be sufficiently ensured. On the other hand, when the above range is exceeded, (a) the amount of carboxyl group-containing units present in the water-soluble polymer decreases, so that it is necessary to increase the amount of the hydrous soil treatment agent used for hydrous soil as described above. become.

  In the present specification, (a) the above-mentioned “structural unit” in the water-soluble polymer means (a) a basic unit constituting the water-soluble polymer, and the carboxyl group-containing unit means such a basic unit. Among them, those containing a carboxyl group and the sulfone group-containing unit mean those containing a sulfone group.

  In addition, in the water-soluble polymer (a), the preferred molar ratio of the carboxyl group and the sulfone group that can be derived from the preferred range of the carboxyl group-containing unit amount and the sulfone group-containing unit amount is 199: 1 to 1: 1. More preferably, the molar ratio is 99: 1 to 4: 1. In addition, the molar ratio of the carboxyl group and the sulfone group in the water-soluble polymer is, for example, a colloid using an aqueous solution adjusted to pH = 2 and an aqueous solution adjusted to pH = 10 according to a conventional method. It can be easily measured by performing a titration.

  (A) The production method of the water-soluble polymer is not particularly limited. For example, a polymerization method using a polymerization initiator such as a radical polymerization initiator; radiation such as ionizing radiation and electron beam; and electromagnetic waves such as ultraviolet rays. Various conventionally known polymerization methods such as a polymerization method to be irradiated; a polymerization method by heating; and the like, and two or more of these polymerization methods can be used in combination.

  In addition, as the polymerization mode, various conventionally known polymerization modes such as suspension polymerization, solution polymerization, emulsion polymerization, bulk polymerization and the like can be employed, and these may be either batch type or continuous type. I do not care.

  The radical polymerization initiator that can be used when the polymerization method using the above-described polymerization initiator is employed is not particularly limited, and examples thereof include ammonium persulfate, potassium persulfate, hydrogen peroxide, benzoyl peroxide, and t-butyl peroxide. A reducing agent suitably used in a redox system such as sodium bisulfite, sodium metabisulfate, ferrous ammonium sulfate, L-ascorbic acid, triethanolamine; 2,2′-azobis (2,4 -Dimethylvaleronitrile), 2,2'-azobis (2-aminopropane) dihydrochloride, 2,2'-azobisisobutyramide dihydrate, 2,2'-azobis [2- (2-imidazoline- Azo initiators such as 2-yl) propane] dihydrochloride, 4,4′-azobis (4-cyanopentanoic acid); Rohexyl-phenyl-ketone (trade name “IRGACURE184”), 2-hydroxy-2-methyl-1-phenyl-propan-1-one (trade name “DAROCUR1173”), eutectic mixture of IRGACURE184 and benzophenone (trade name “IRGACURE184”) IRGACURE500 ”), 2,2-dimethoxy-1,2-diphenylethane-1-one (trade name“ IRGACURE651 ”), bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide (trade name“ IRGACURE819 ”) ) 2-Methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one (trade name “IRGACURE907”), 2-benzyl-2-dimethylamino-1- (4-morpholino) Phenyl) -butanone-1 (trade name “IRGACURE369”) and IRGACURE651 3: 7 mixture (trade name “IRGACURE1300”), bis (2,6-dimethoxybenzoyl) -2 1: 3 mixture of 4,4-trimethyl-pentylphosphine oxide and IRGACURE184 (trade name “IRGACURE1800”), 1: 1 liquid mixture of 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide and DAROCUR1173 ( Photoinitiators such as “DAROCUR4265”) and 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide (trade name “DAROCUR TPO”) (both “IRGACURE” and “DAROCUR” are both It is a photoinitiator manufactured by Specialty Chemicals Co., Ltd.); In addition, the usage-amount of a polymerization initiator, the conditions of a polymerization reaction, etc. are not specifically limited, What is necessary is just to determine suitably according to the kind, amount, etc. of a monomer to be used.

  The weight average molecular weight of the (a) water-soluble polymer is not particularly limited, but is, for example, 100,000 or more, more preferably 500,000 or more, more preferably 1,000,000 or more, and 20 million or less, more preferably 10 million. It is recommended that: If the weight average molecular weight exceeds the above range, the dissolution rate in water may decrease, and the hydrous soil treatment agent containing such a water-soluble polymer as a constituent element increases the viscosity when mixed with hydrous soil. There is a risk that it will be difficult to uniformly mix the two due to the effect, and the synthesis of the polymer itself tends to be difficult. On the other hand, when the weight average molecular weight is less than the above range, the hydrous soil treatment using the water-soluble polymer may lower the hydrous soil treatment performance (granulation performance). In general, as a result of studies by the present inventors, the weight average molecular weight of the water-soluble polymer (a) tends to be superior in water-containing soil treatment performance on the high molecular weight side even within the above range. It has been found.

  Incidentally, from the viewpoint of handleability of the hydrous soil treatment agent, (a) a suitable viscosity of the aqueous solution of the water-soluble polymer is, for example, preferably 5 to 10,000 mPa · s at 25 ° C. when the concentration is 0.2% by mass. Is 10 to 2000 mPa · s. Therefore, it is also preferable to adjust the weight average molecular weight of (a) water-soluble polymer so that such aqueous solution viscosity can be achieved.

  As described above, in (a) the water-soluble polymer, the carboxyl group contained in these may be present in the form of a free carboxyl group or a carboxylate group, but it contains a free carboxyl group. Is more preferable. Specific examples of the carboxylate group include alkali metal salts such as sodium salts and potassium salts; alkaline earth metal salts such as calcium salts and magnesium salts; ammonium salts; amine salts; It is not necessarily limited to.

  (A) In 100 mol% of the carboxyl groups contained in the water-soluble polymer, the proportion of free carboxyl groups is preferably 5 mol% or more, more preferably 20 mol% or more, further preferably 40 mol% or more, particularly preferably 60 mol% or more. preferable. When the ratio of the free carboxyl group is below the lower limit, the water-containing soil treatment performance using such a water-soluble polymer may deteriorate the water-containing soil treatment performance. Depending on the nature of the hydrous soil to be treated (eg, hydrous soil discharged in the Kanto region), the ratio of free carboxyl groups is most preferably 100 mol%.

  (A) In the case where the water-soluble polymer has a carboxylic acid group or a sulfonic acid group, those containing a carboxylic acid group or a sulfonic acid group as a monomer for forming the (a) water-soluble polymer In addition to synthesis using a monomer, a polymer is synthesized once using a monomer having a free carboxyl group or a free sulfone group, and then part or all of the free carboxyl group or free sulfone group is neutralized. Thus, a salt (carboxylate group, sulfonate group) may be used. Examples of alkalis that can be used for neutralization include hydroxides and carbonates of alkali metals such as sodium, potassium, and lithium; ammonia; alkylamines such as monomethylamine, diethylamine, trimethylamine, monoethylamine, dimethylamine, and triethylamine; Alkanolamines such as monoethanolamine, diethanolamine, triethanolamine, isopropanolamine and secondary butanolamine can be mentioned, and sodium hydroxide and carbonate are common.

  In addition, (a) the sulfone group in the water-soluble polymer is a group that the polymerizable monomer for forming the (a) water-soluble polymer previously had, or a specific polymer is post-modified. The group introduced by this may be sufficient.

  In introducing the sulfone group by post-modification, the base polymer (polymer for post-modification) includes, for example, the above-exemplified carboxyl group-containing monomer and, if necessary, the above-exemplified sulfone group-containing monomer. And other monomers (in addition to the monomers exemplified above, for example, those having two or more double bonds in the molecule such as butadiene and isoprene) can be obtained by polymerizing by various methods exemplified above. Things can be used. Among such post-modification polymers, poly (meth) acrylic acid is preferred, and polyacrylic acid is more preferred.

  As a post-modification method for introducing a sulfone group into the above-mentioned post-modification polymer, a method of reacting the polymer with a sulfone group-introducing compound described later can be employed. For example, a method in which a carboxyl group contained in a post-modification polymer and a hydroxyl group contained in sodium isethionate (sodium hydroxyethane sulfonate) as a sulfone group-introducing compound are ester-bonded; An amide bond between the carboxyl group to be synthesized and the amino group contained in the sulfone group-introducing compound taurine sodium salt (sodium aminoethanesulfonate); post-modification using fuming sulfuric acid as the sulfone group-introducing compound, etc. A method of sulfonating a polymer for use; a method of adding a sulfone group-introducing compound, sodium bisulfite, to a double bond contained in a post-modification polymer; Absent.

  The sulfone group-introducing compound is not particularly limited as long as it can introduce a sulfone group into the post-modification polymer. Specific examples other than the compounds exemplified above include compounds suitable for ester bond formation such as sodium hydroxymethanesulfonate and sodium hydroxypropanesulfonate; suitable for amide bond formation such as sodium aminomethanesulfonate and aminopropanesulfonic acid. Compound etc. are mentioned.

  The post-modification reaction method and conditions are not particularly limited, and may be appropriately selected according to the sulfone group-introducing compound to be used and the type of the reaction. For example, a method in which a post-modification polymer and a sulfone group-introducing compound are mixed and heated can be employed. Further, the amount of the sulfone group-introducing compound to the post-modification polymer is not particularly limited, and according to the type of the polymer and the compound, a combination thereof, or the like so that the necessary sulfone group amount can be satisfied. What is necessary is just to determine suitably. Further, as the post-modification polymer, (a) a water-soluble polymer can be used, and the above-mentioned post-modification can be carried out for the purpose of increasing the amount of the sulfone group in the water-soluble polymer.

  In the case of quantifying the amount of the sulfone group-containing unit in the water-soluble polymer into which the sulfone group was introduced by post-modification, the basic unit into which the sulfone group was introduced by post-modification was also included in the sulfone group-containing unit. To do.

  (A) When the water-soluble polymer is used in the hydrous soil treatment agent of the present invention, the polymer may be an aqueous solution, an emulsion, or a powder. In addition, (a) Depending on the type and molecular weight of the water-soluble polymer, the aqueous solution has a very high viscosity, the handleability may be reduced, or the miscibility with the hydrous soil may be reduced during the hydrous soil treatment. Therefore, when (a) the water-soluble polymer is used as an aqueous solution, it may be necessary to reduce the viscosity by using a large amount of water to reduce the concentration of the aqueous solution. Therefore, in consideration of handleability and miscibility with water-containing soil, the water-soluble polymer is preferably dried and pulverized as necessary and used as a powder. In addition, the drying method and the grinding | pulverization method of (a) water-soluble polymer are not specifically limited, What is necessary is just to employ | adopt a conventionally well-known method.

  (A) When the water-soluble polymer is used as a powder (particle), the average particle size is preferably 0.01 to 2 mm, and more preferably 0.02 to 1 mm. If the average particle size is in such a range (a) a water-soluble polymer, even if a treatment agent comprising this water-soluble polymer as a constituent element is mixed with water-containing soil, it is difficult to be spoiled and the handling property is also good. It is.

  In the hydrous soil treatment agent of the present invention, (b) smectite clay is also one of the components.

  Smectite clay is a kind of phyllosilicate (layered silicate) mineral. It has a 2: 1 structure formed by stacking 2: 1 layers of two Si-O tetrahedral sheets and one octahedral sheet. However, as a structural feature compared to other phyllosilicate minerals, sodium ions and calcium ions are included between the stacked 2: 1 layers. Since these ions existing between the layers can exist more stably when combined with water, the smectite clay has a feature that it can absorb and retain a large amount of water between the layers. That is, the water-containing soil treatment agent of the present invention is intended to granulate water-containing soil by fixing the water contained in the water-containing soil by both (a) a water-soluble polymer and (b) smectite clay. It is.

  (B) As a smectite clay, a main smectite clay mineral and montmorillonite such as beidellite, nontronite, saponite, hectorite, soconite, stevensite, swinholderite, montmorillonite, and bolconcoreite are mainly used. The bentonite which is clay is mentioned. In addition to naturally occurring smectite clay minerals, modified ones thereof, such as modified bentonite obtained by artificially modifying Ca-type bentonite to Na-type bentonite, and synthetically synthesized smectite ( A trade name “Lucentite” (manufactured by Coop Chemical Co., Ltd.) and synthetic hectorite (trade name “Laponite”, manufactured by Toshin Kasei Co., Ltd.) are also preferably used. Among these, it is preferable to use bentonite having montmorillonite as a main component mineral, and it is particularly preferable to use Na-type bentonite exhibiting high swellability.

  The form of the (b) smectite clay in the hydrous soil treatment agent of the present invention is not particularly limited, and may be a state dispersed in water or a powder. In consideration of handleability and mixability with hydrous soil, (b) smectite clay is preferably used as a powder. In this case, the particle size (average particle size) of (b) smectite clay is preferably 0.001 to 5 mm, and more preferably 0.005 to 0.1 mm.

  The water-containing soil treatment agent of the present invention can solidify the treated granular soil by itself, but if further improvement in strength is required for the granular soil, etc., (c) hydraulic substance Can also be used. (C) The hydraulic substance is not particularly limited as long as it is a substance that cures in water, and examples thereof include cement, quicklime, slaked lime, gypsum (semihydrate gypsum, anhydrous gypsum), and mixtures thereof. . Among the hydraulic materials exemplified above, cement is preferable. In the granulation method of the present invention using the above-mentioned hydrous soil treatment agent, in a normal mode, (c) the hydraulic substance contains (a) a water-soluble polymer and (b) smectite clay in the hydrous soil. It is preferable to add after mixing and dispersing (details will be described later).

  Various known cements can be used as the cement. Examples include, but are not limited to, Portland cement such as ordinary Portland cement, early-strength Portland cement, and ultra-early strong Portland cement; blast furnace cement; alumina cement; calcium cement; fly ash cement; Among them, blast furnace cement can be preferably used in that elution of hexavalent chromium, which is a heavy metal, is not substantially observed.

  In addition, in the water-containing soil treatment agent of the present invention, water-absorbing resin, water-absorbing fiber material (cellulose, pulp, recovered waste paper, etc.), talc, alumina, kaolin, silica, zeolite, perlite, quartz sand, diatomaceous earth, fly ash and acid clay Etc. may be used for some of them as necessary.

  A preferred form of the hydrous soil treatment agent of the present invention is (1) a powdery (a) water-soluble polymer and a powdery (b) smectite clay premixed, (2) (a) a liquid in which a smectite clay is dispersed in an aqueous solution or emulsion of a water-soluble polymer, (3) a powdery (a) water-soluble polymer, and a powdery ( b) A form in which smectite clay is separately packaged, (4) A form in which (a) an aqueous solution or emulsion of a water-soluble polymer and powdered (b) smectite clay are separately packaged. , Etc. can be employed. In the case where (c) a hydraulic substance is also used as a constituent element, the hydraulic substance is (a) a water-soluble polymer or a powdery ( b) It is preferable to employ the smectite clay in a separately packaged form. The reason for this will be described later.

  The granulation method of the hydrous soil by the hydrous soil treatment agent of each of the above forms is as follows. In the case of the above-mentioned forms (1) and (2), (a) the water-soluble polymer and the powdery (b) smectite clay are simultaneously mixed and treated (granulated) in the hydrous soil. In the case of the above forms (3) and (4), the separately packaged (a) water-soluble polymer and the powdered (b) smectite clay can be mixed and treated simultaneously with the hydrous soil. However, it is also possible to employ a method in which one of (a) a water-soluble polymer and (b) smectite clay is first mixed and then the other component is mixed. In this case, the time until the other component is added after mixing (a) the water-soluble polymer or (b) smectite clay is not particularly limited. In addition, after the treatment of the hydrous soil, that is, in the case of the above forms (1) and (2), after mixing (a) the water-soluble polymer and (b) the smectite clay into the hydrous soil. In the case of (3) or (4) above, the time (total treatment time) from mixing any one of the components to the hydrous soil until the completion of the hydrous soil treatment may be 420 seconds or less. desirable.

  The (c) hydraulic substance may be added after (a) the water-soluble polymer and (b) the smectite clay are mixed with the water-containing soil and dispersed, or after being granulated, (A) After adding and mixing the water-soluble polymer to the hydrous soil, (b) smectite clay and (c) hydraulic substance may be added simultaneously. When (c) a hydraulic substance is added prior to the addition of (a) a water-soluble polymer to a hydrous soil, granulation of the hydrous soil may become difficult.

  The method of mixing the hydrous soil with (a) the water-soluble polymer and (b) smectite clay is not particularly limited, but it is preferable to use a mixer capable of stirring and mixing these without kneading them. For example, an apparatus including a stirring blade having a shape of a rod or a fishhook so that the mixture can be stirred while applying a shearing force is suitable. That is, when the stirring blade has a shape that expands in the direction perpendicular to the moving direction of the mixture that moves by stirring and mixing, it is possible to suppress coarsening of the particle diameter due to kneading, and the stirring blade and the inner wall of the apparatus This is desirable because it can prevent the mixture from adhering to the surface.

  Examples of such an apparatus include a horizontal axis mixer and a vertical axis mixer. As a horizontal axis type mixer, a single axis and a multi-axis paddle type mixer are preferable. As the vertical shaft type mixer, for example, a pan mixer type mixer is preferable, a planetary type mixer is more preferable, and among these planetary type mixers, a soil mixer, a mortar mixer, and an Eirich mixer are particularly preferable.

  A shorter time to granulation is preferable from the viewpoint of work efficiency, and is usually within a few minutes. By stirring, the hydrous soil becomes a smooth sandy granular soil. The particle size of the granular soil is preferably about 0.1 to 100 mm, and more preferably 0.1 to 40 mm.

  (C) Although the method of mixing the hydraulic substance is not particularly limited, the water-containing soil in which (a) the water-soluble polymer and (b) smectite clay are mixed and dispersed is mixed with (c) the hydraulic substance. It is desirable to use the above-mentioned apparatus which can be stirred and mixed without any problems. In addition, when the hydrous soil is already granulated by mixing (a) a water-soluble polymer and (b) smectite clay, (c) adhering the hydraulic substance to the surface of the granular soil (c) Is desirable. Alternatively, (c) a part of the hydraulic substance may be taken into the granular soil.

  The amount of treatment agent used in the treatment of hydrous soil varies depending on the mode of hydrous treatment (water content ratio, viscosity, type of soil component, etc.). For example, for 100 parts by mass of hydrous soil, (a) It is recommended that the amount of coalescence be 0.01 parts by mass or more, 5 parts by mass or less, more preferably 1 part by mass or less. The amount of (b) smectite clay used is 0.1 parts by mass or more, 100 parts by mass or less, more preferably 0.5 parts by mass or more, with respect to 100 parts by mass of the hydrous soil. It is desirable that the amount is not more than part by mass. Furthermore, (c) when using a hydraulic substance, the usage-amount is 1 mass part or more with respect to 100 mass parts of hydrous soil, Comprising: 35 mass parts or less, More preferably, you may be 20 mass parts or less. It is recommended. Therefore, what is necessary is just to determine the usage-ratio of each component in the hydrous soil treatment agent of this invention within the range of the said preferable usage-amount of each component with respect to 100 mass parts of hydrous soil. For example, the mixing ratio of the above-mentioned (a) water-soluble polymer and (b) smectite clay is preferably 1: 0.1 or more, more preferably 1: 1 or more, and 1: 10000 or less by mass ratio. It is recommended that the ratio be 1: 1000 or less.

  In water-containing soil, even if the water content ratio is the same, the viscosity varies depending on the component composition of the soil, and the ease of treatment also varies. Taking into account the effects of such differences in component composition and the like, as an index for evaluating characteristics related to the viscosity of hydrous soil, for example, there is a flow value obtained by the measurement method described later, the hydrous soil treatment agent of the present invention and In the treatment method, not only soil with a relatively low water content of a flow value of about 55 mm or more and less than 70 mm, which is a target for conventional treatment agents, but also soil with a high water content or low viscosity of about 70 mm or more and 1000 mm or less. However, it is possible to obtain a granular soil having a particle size of a conventional level with a small amount of use as described above, and it has a very excellent hydrous soil treatment performance.

  The flow value is obtained as follows. When a hollow cylinder with an inner diameter of 55 mm and a height of 55 mm is placed on a table, and the wet soil is filled in the cylinder, the diameter of the wet soil spread on the table is measured in two directions when the cylinder is lifted vertically. The average value is used as the flow value.

  The granular soil obtained by the treatment agent and granulation method of the present invention can be transported by truck, and can be reused for various applications such as backfill material as a substitute for sand.

  Hereinafter, the present invention will be described in detail based on examples. However, the following examples are not intended to limit the present invention, and all modifications made without departing from the spirit of the preceding and following descriptions are included in the technical scope of the present invention. In this example, “part” is based on mass unless otherwise specified.

<Water-soluble polymer>
Water-soluble polymer A
The water-soluble polymer A is a copolymer of acrylic acid: 90 mol% and sodium 2-acrylamido-2-methylpropanesulfonate: 10 mol%, and is synthesized by the following production method.

  In a 5 L stainless steel separable flask (I) equipped with a stirrer, thermometer, reflux condenser, and nitrogen introduction tube, cyclohexane: 1000 g, sorbitan monostearate: 13.5 g were added, and 50 ml / min with stirring. Nitrogen was introduced at a rate and the temperature was raised to 70 ° C.

  In a 2 L separable flask (II) equipped with a stirrer, thermometer, reflux condenser, and nitrogen introduction tube, acrylic acid: 332.5 g, 2-acrylamido-2-methylpropanesulfonic acid: 106.2 g, 48% by mass Aqueous sodium hydroxide solution: 42.8 g and ion exchange water: 391.8 g were added and dissolved by stirring. Further, while continuing stirring, nitrogen was introduced into the solution of the separable flask (II) for 25 minutes (the dissolved oxygen concentration of the solution was 1 mg / L or less), and then 2,2′-azobis [2- (2-imidazoline- 2-yl) propane] dihydrochloride is 0.03% by mass, 4,4′-azobis (4-cyanopentanoic acid) is 0.04% by mass, and sodium hypophosphite monohydrate is 0.01%. Mass% aqueous solution: 126.9 g was added to the solution in the separable flask (II), and nitrogen was further introduced for 5 minutes.

  Thereafter, the contents of the separable flask (II) were fed to the separable flask (I) over 2 hours for polymerization, and aged for 30 minutes. Next, 6.50% by mass of 2,2′-azobis [2- (2-imidazolin-2-yl) propane] dihydrochloride aqueous solution: 5.9 g was added to the separable flask (I), and further aged for 30 minutes. went. Subsequently, dehydration was performed, followed by cooling to 30 ° C. or lower, solid-liquid separation of the contents, and drying to obtain a water-soluble polymer A (white fine particles).

  A 0.2 mass% aqueous solution of this water-soluble polymer was measured with a B-type viscometer using a rotor: The viscosity at 25 ° C. measured at 2 and 30 rpm was 115 mPa · s. The degree of neutralization was 10%.

Water-soluble polymer B
The water-soluble polymer B is a copolymer of acrylic acid: 80 mol%, sodium acrylate: 15 mol%, and sodium 2-acrylamido-2-methylpropanesulfonate: 5 mol%, and was synthesized by the following production method. is there.

  In a 5 L stainless steel separable flask (I) equipped with a stirrer, thermometer, reflux condenser, and nitrogen introduction tube, cyclohexane: 1000 g, sorbitan monostearate: 13.5 g were added, and 50 ml / min with stirring. Nitrogen was introduced at a rate and the temperature was raised to 70 ° C.

  In a 2 L separable flask (II) equipped with a stirrer, thermometer, reflux condenser, and nitrogen introduction tube, acrylic acid: 370.2 g, 2-acrylamido-2-methylpropanesulfonic acid: 56.0 g, 48% by mass Sodium hydroxide aqueous solution: 90.2 g and ion exchange water: 360.2 g were added and dissolved by stirring. Nitrogen is introduced for 25 minutes with stirring to reduce the dissolved oxygen of the solution to 1 mg / L or less, and 2,2′-azobis [2- (2-imidazolin-2-yl) propane] dihydrochloride is added here. : An aqueous solution comprising 0.07% by mass, 0.04% by mass of 4,4′-azobis (4-cyanopentanoic acid), and 0.02% by mass of sodium hypophosphite monohydrate: 123.6 g And nitrogen was introduced for an additional 5 minutes.

  Thereafter, the mixture prepared in the separable flask (II) was fed to the separable flask (I) over 2 hours for polymerization, and after aging for 30 minutes, 7.16% by mass 2,2′-azobis [2 -(2-Imidazolin-2-yl) propane] dihydrochloride aqueous solution: 5.7 g was added to the separable flask (I) and aged for another 30 minutes. Subsequently, dehydration was performed, followed by cooling to 30 ° C. or lower, solid-liquid separation of the contents, and drying to obtain a water-soluble polymer B (white fine particles).

  A 0.2 mass% aqueous solution of this water-soluble polymer was measured with a B-type viscometer using a rotor: No. The viscosity at 25 ° C. measured at 2 and 30 rpm was 230 mPa · s. The degree of neutralization was 20%.

Water-soluble polymer C
As the water-soluble polymer C, sodium polyacrylate having a weight average molecular weight (MW) of 4 to 5 million was used.
<Evaluation soil>
The evaluation soil is a hydrous soil formed by thoroughly mixing Toyoura standard sand: 5 parts, silt: 75 parts, clay: 270 parts, and tap water: 350 parts. About this evaluation soil, the flow value calculated | required by the above-mentioned measuring method was 250 mm.

Experimental example 1
Evaluation soil: 100 parts are charged into a mixer equipped with a beater-type stirring blade, and while stirring at 160 rpm, water-soluble polymer A: 0.25 parts and bentonite (Kunigel V1, manufactured by Kunimine Kogyo Co., Ltd.): 5 parts After adding a pre-mixed treatment agent and stirring for 240 seconds (in addition, the state of soil modification at this stage is about 1-2 according to the evaluation criteria in Table 2 below), Portland cement (Pacific cement) (Made by Co., Ltd.): 5 parts were added, and the evaluation soil was further treated by stirring for 60 seconds. The state of the evaluation soil after the treatment was evaluated according to the criteria shown in Table 1. The results are shown in Table 2.

Experimental example 2
The same treatment as in Example 1 was performed except that 0.25 part of water-soluble polymer A and synthetic smectite (trade name “Lucentite”, manufactured by Co-op Chemical Co., Ltd.): 5 parts were used as treatment agents. Then, the evaluation soil was treated. The state of the evaluation soil after the treatment was evaluated according to the criteria shown in Table 1. The results are shown in Table 2.

Experimental example 3
The evaluation soil was treated in the same manner as in Example 1 except that 5 parts of blast furnace cement (type B blast furnace cement, manufactured by Taiheiyo Cement) was used instead of Portland cement. The state of the evaluation soil after the treatment was evaluated according to the criteria shown in Table 1. The results are shown in Table 2.

Experimental Example 4
Evaluation soil: 100 parts were charged into a mixer equipped with a beater-type stirring blade, and while being stirred at 160 rpm, a treatment agent in which water-soluble polymer A: 0.25 parts and bentonite: 5 parts were mixed in advance and Portland cement : 5 parts were added simultaneously and stirred for 80 seconds to treat the evaluation soil. The state of the evaluation soil after the treatment was evaluated according to the criteria shown in Table 1. The results are shown in Table 2.

Experimental Example 5
Evaluation soil: 100 parts were charged into a mixer equipped with a beater-type stirring blade, and a processing agent in which water-soluble polymer A: 0.10 parts and bentonite: 5 parts were mixed in advance was added while stirring at 160 rpm. After stirring for 240 seconds, 5 parts of quicklime was added, and further stirred for 60 seconds to treat the evaluation soil. The state of the evaluation soil after the treatment was evaluated according to the criteria shown in Table 1. The results are shown in Table 2.

Experimental Example 6
The evaluation soil was treated in the same manner as in Example 1 except that 0.12 part of water-soluble polymer A and 5 parts of bentonite were mixed in advance as the treating agent. The state of the evaluation soil after the treatment was evaluated according to the criteria shown in Table 1. The results are shown in Table 2.

Experimental Example 7
Evaluation soil: 100 parts were charged into a mixer equipped with a beater-type stirring blade, and while stirring at 160 rpm, a treatment agent in which 0.25 parts of water-soluble polymer A and 10 parts of bentonite were mixed in advance was added, The evaluation soil was treated by stirring for 420 seconds. The state of the evaluation soil after the treatment was evaluated according to the criteria shown in Table 1. The results are shown in Table 2.

Experimental Example 8
The evaluation soil was treated in the same manner as in Example 1 except that a water-soluble polymer B: 0.25 part and bentonite: 5 parts were used in advance as a treating agent. The state of the evaluation soil after the treatment was evaluated according to the criteria shown in Table 1. The results are shown in Table 2.

Experimental Example 9
Evaluation soil: 100 parts were charged into a mixer equipped with a beater-type stirring blade and stirred at 160 rpm for 240 seconds, then Portland cement: 10 parts were added, and the evaluation soil was treated by stirring for 60 seconds. That is, this experimental example is an example in which neither a water-soluble polymer nor a smectite clay is used. The state of the evaluation soil after the treatment was evaluated according to the criteria shown in Table 1. The results are shown in Table 3.

Experimental Example 10
Evaluation soil: 100 parts were charged into a mixer equipped with a beater type stirring blade, and while stirring at 160 rpm, 0.25 part of water-soluble polymer A was added and stirred for 240 seconds. Next, Portland cement: 5 parts was added thereto, and the evaluation soil was further treated by stirring for 60 seconds. The state of the evaluation soil after the treatment was evaluated according to the criteria shown in Table 1. The results are shown in Table 3.

Experimental Example 11
The evaluation soil was treated in the same manner as in Comparative Example 10 except that the amount of Portland cement added was 10 parts. The state of the evaluation soil after the treatment was evaluated according to the criteria shown in Table 1. The results are shown in Table 3.

Experimental Example 12
As the treating agent, 0.25 part of water-soluble polymer A and talc (trade name “LMP # 100”, manufactured by Fuji Talc Kogyo Co., Ltd.): 5 parts in advance were used, except that 5 parts were used. The evaluation soil was treated in the same manner. The state of the evaluation soil after the treatment was evaluated according to the criteria shown in Table 1. The results are shown in Table 3.

Experimental Example 13
As the treating agent, 0.25 parts of water-soluble polymer A and kaolin (trade name “AstraGlaze” manufactured by Imerizu Minerals Japan Ltd.): 5 parts were used in the same manner as in Experimental Example 1 except that 5 parts were mixed in advance. Then, the evaluation soil was treated. The state of the evaluation soil after the treatment was evaluated according to the criteria shown in Table 1. The results are shown in Table 3.

Experimental Example 14
Evaluation soil: 100 parts were charged into a mixer equipped with a beater-type stirring blade, while stirring at 160 rpm, water-soluble polymer A: 0.25 parts, talc (trade name “LMP # 100”, Fuji Talc Industrial Co., Ltd.) (Opened company): 5 parts of a pre-mixed treatment agent and Portland cement: 5 parts were added simultaneously and stirred for 80 seconds to treat the evaluation soil. The state of the evaluation soil after the treatment was evaluated according to the criteria shown in Table 1. The results are shown in Table 3.

Experimental Example 15
Evaluation soil: 100 parts were charged into a mixer equipped with a beater-type stirring blade, and while stirring at 160 rpm, 0.25 part of water-soluble polymer C was added and stirred for 240 seconds. Subsequently, 10 parts of Portland cement was added thereto, and the evaluation soil was further treated by stirring for 60 seconds. The state of the evaluation soil after the treatment was evaluated according to the criteria shown in Table 1. The results are shown in Table 3.

Experimental Example 16
Evaluation soil: 100 parts are charged into a mixer equipped with a beater-type stirring blade, and while being stirred at 160 rpm, a treatment agent in which water-soluble polymer C: 0.25 part, bentonite: 5 parts are mixed in advance, and Portland cement : 5 parts were added simultaneously and stirred for 80 seconds to treat the evaluation soil. The state of the evaluation soil after the treatment was evaluated according to the criteria shown in Table 1. The results are shown in Table 3.

  Those with an evaluation value of 4 or more after treatment in Table 1 are acceptable, those with 3 or less are unacceptable, and those with higher evaluation values are more suitable as backfill materials, embankment materials, horticultural soils as resources such as sand substitutes. Used for. For example, those having evaluation values 4 and 5 have been granulated to such an extent that they can be easily transported by a truck or the like, and can be used as a backfill material depending on the place of application. About the thing of the evaluation values 6-9, it can use suitably as a backfill material, embankment material, and gardening soil.

  In Tables 2 and 3, among the methods of adding smectite clay or its substitute and hydraulic substance, “mixing” means mixing the water-soluble polymer and smectite clay or its substitute in advance into the evaluation soil. “Post-addition” means that a hydraulic substance has been added to the evaluation soil to which a water-soluble polymer and smectite clay or its substitute have been added and mixed. This means that the water-soluble polymer, smectite clay or its substitute, and the hydraulic substance were simultaneously added to and mixed with the evaluation soil. The numerical value of “granulated state” means the evaluation value in Table 1.

  From Table 2, in Experimental Examples 1-4, 7 and 8 using the water-containing soil treatment agent of the present invention containing a water-soluble polymer and smectite clay, a very high level (granulated state: It can be seen that the water-containing soil is granulated up to 8, 9). Further, from Experimental Example 5 and Experimental Example 6, if smectite clay is used in combination, even if the amount of water-soluble polymer used is reduced to less than half, it is sufficiently high to a level suitable as a backfill material or embankment material. It can be seen that the hydrous soil can be granulated (granulated state: 6, 7). In addition, regarding the method of adding smectite clay and hydraulic substance, the addition of hydraulic substance after adding and mixing water-soluble polymer and smectite clay in advance to the hydrous soil is the granulation of hydrous soil. (Experimental example 4).

On the other hand, Table 3 shows examples in which smectite clay was not used (Experimental Examples 9 to 15). For example, in Experimental Example 9 in which only a hydraulic substance was used, the water-containing soil was not granulated at all. In Experimental Examples 10 and 11, the same amount of water-soluble polymer as in Experimental Examples 1 to 4 in which the water-containing soil was granulated to a very high level was used, but smectite clay was used. Therefore, it can be seen that the amount of water-soluble polymer is only granulated to the same extent as Experimental Example 6 in which the amount used was reduced to half (granulated state: 5 [Experimental Example 10], 6 [Experimental Example 11]). ).
From these results, it can be seen that the combined use of smectite clay can granulate hydrous soil to a very high level that cannot be achieved with water-soluble polymers or hydraulic substances alone.

  Furthermore, the excellent granulation effect like this invention is not acquired also in Experimental Examples 12-14 using the smectite clay substitute. That is, even if the clay mineral is classified into the same phyllosilicate, the effect on granulation of the hydrous soil is greatly different. Especially, smectite clays such as bentonite are classified as other phyllosilicates. It can be seen that it has a greater effect on granulation of hydrous soil than minerals. Experimental Examples 15 and 16 are examples in which sodium polyacrylate was used as the water-soluble polymer C. The water-soluble polymer C is different from the water-soluble polymer (a) according to the present invention in which the granulation performance is improved by improving the solubility and salt resistance in water-containing soil. Since it was difficult to dissolve in the hydrous soil and the granulation performance was insufficient, the hydrous soil was not granulated at all (granulation state: 1). Even when the water-soluble polymer C was used in combination with bentonite and a hydraulic substance, it was difficult to granulate the hydrous soil (Experimental Example 16).

  From the above results, it can be seen that according to the present invention in which (a) the water-soluble polymer and smectite clay are used in combination, the hydrous soil can be granulated to a very high level.

Claims (5)

(A) It contains a carboxyl group (including a carboxylate group) and a sulfone group (including a sulfonate group, the same applies hereinafter), and the sulfone group-containing unit is 0.5 to 50 mol% in 100 mol% of all the constituent units. A water-soluble polymer;
(B) Smectite clay,
A water-containing soil treatment agent characterized by comprising:   The hydrous soil treatment agent according to claim 1, further comprising (c) a hydraulic substance as a constituent element.   A method for granulating water-containing soil, comprising mixing the water-containing soil treatment agent according to claim 1 or 2 with water-containing soil.   The granulation according to claim 3, wherein (a) the water-soluble polymer and (b) smectite clay are mixed with the water-containing soil, and then the water-containing soil is granulated, and then (c) a hydraulic substance is mixed. Method.   A granular soil obtained by the granulated method of hydrous soil according to claim 3 or 4.