JPH11217565A - Improving agent for water-containing soil and improvement of the soil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an improving agent which is suitable for improving water- containing soil and recycling the soil, and provide a method for improving the soil. SOLUTION: This improving agent for water-containing soil comprises a polymer obtained by polymerizing a monomer component having >=5,000,000 weight-average molecular weight and containing >=85 mol.% carboxyl group- containing monomer. The method for improving water-containing soil comprises improving the water-containing soil to solidified material formed into fine particles having sufficient strength and a prescribed particle diameter by mixing the water-containing soil with the improving agent comprising the above polymer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an agent for improving water-containing soil and a method for improving water-containing soil, and more particularly, to a method suitable for reusing sand as a substitute. The present invention relates to an improving agent and an improving method for improving a hydrated soil into granules.

[0002]

2. Description of the Related Art Generally, for example, in the treatment of construction waste material resulting from excavation work using a cast-in-place pile method, a mud shield method, or the like, excavated soil generated during excavation is supplied by supplying excavated mud to an excavation hole. Is discharged to the outside together with the drilling mud.

[0003] The above-mentioned generated soil is not classified as industrial waste specified in the Waste Disposal and Waste Management Law, because earth and sand are separated and reused for cutting at construction sites. However, excavated muddy water, which has a muddy state, more specifically, a slurry containing a large amount of water together with clay, and exhibits fluidity, cannot be piled up on a standard specification dump truck, and for example, a person can walk on it. Has no state. Therefore, the above drilling mud is
It cannot be used as backfill material as it is, but must be treated as industrial waste in accordance with the Waste Management Law. For this reason, the above-mentioned excavated mud is subjected to dewatering press or the like to carry out solid-liquid separation so that it can be transported or the like. Coalescence and the like are mixed and solidified (improved). The hydrous soil improved by these improvement methods is discarded at a predetermined disposal site such as a landfill disposal site, or the improved hydrous soil is used in civil engineering work in which excavation holes need to be backfilled. Is injected into a wellbore.

[0004] As such an improved method, for example, Japanese Patent Application Laid-Open No. 1-176499 discloses a method of mixing a water-soluble synthetic polymer substance or the like with water-containing soil.

[0005]

However, since water-containing soil must be treated as industrial waste, it requires a great deal of disposal costs. In addition, the final disposal amount of hydrous soil as construction waste material is enormous, and landfill disposal of hydrous soil is difficult every day due to difficulties in obtaining land for final disposal sites to dispose of hydrous soil and opposition from local residents. Has become. Therefore, when the hydrous soil is treated by the above-mentioned conventional improvement method, there is also a problem that it is difficult to secure land for a final disposal site such as a disposal site. For this reason, there is a long-felt need for an improved method capable of reusing water-containing soil.

[0006] The present invention has been made in view of the above-mentioned conventional problems, and an object of the present invention is to provide an improving agent and an improving method suitable for improving and reusing hydrous soil. is there.

[0007]

Means for Solving the Problems The present inventors have diligently studied an improving agent and a method for improving a hydrous soil in order to achieve the above object. As a result, the weight average molecular weight is 5,000
The water-containing soil is solidified by mixing the water-containing soil with an improver composed of a polymer obtained by polymerizing a monomer component having a carboxyl group-containing monomer of 85% by mole or more, which is larger than 0,000. The present inventors have found that they can be reused without discarding them, and have completed the present invention.

That is, in order to solve the above-mentioned problems, the water-improved soil improver according to the first aspect of the present invention has a simple structure having a weight average molecular weight of more than 5,000,000 and a carboxyl group-containing monomer of 85 mol% or more. It is characterized by containing a polymer obtained by polymerizing a monomer component.

According to a second aspect of the present invention, in order to solve the above-mentioned problems, in the first aspect of the present invention, the polymer comprises a free carboxyl group. It is characterized by doing.

According to a third aspect of the present invention, there is provided a hydrous soil conditioner according to the first or second aspect, wherein the carboxyl group-containing monomer is (meth) acrylate. ) Acrylic acid.

According to a fourth aspect of the present invention, there is provided a water-containing soil improver according to any one of the first to third aspects of the present invention, in order to solve the above-mentioned problems. However, it is characterized in that it is sodium polyacrylate having a weight average molecular weight of 6,000,000 or more containing free carboxyl groups of 60 mol% or more.

According to a fifth aspect of the present invention, there is provided a water-containing soil improver comprising a polymer having a carboxyl group and a 0.2% by weight aqueous solution having a viscosity of 10 cps or more. And

According to a sixth aspect of the present invention, there is provided a method for improving a hydrous soil, in which the above-mentioned problem is solved by mixing the hydrous soil improving agent according to any one of the first to fifth aspects with the hydrous soil. It is characterized by:

According to a seventh aspect of the present invention, there is provided a method for improving a hydrous soil according to the sixth aspect of the present invention, wherein the above-mentioned hydrous soil is improved to a granular form. I have.

According to each of the above-mentioned structures, it is possible to transport the hydrous soil, which is usually discarded as sludge, by truck, for example, a solidified material improved to a state where a person can walk on it, more preferably It can be improved to a solidified product having sufficient strength and a predetermined particle size and finely divided into particles. As a result, the improved hydrous soil can be effectively used for backfilling, agricultural and horticultural purposes, and the like, for example, as a substitute for sand, and can be reused as resources. Also,
If the hydrous soil after improvement is made into a granular solidified product, water permeability when backfilled on the ground can be improved, and the hydrous soil can be reused in a wider range. As a result, environmental conservation, resource saving, and the life of the disposal site can be prolonged, and the disposal cost of hydrous soil can be reduced.

Hereinafter, the present invention will be described in detail. The hydrated soil solidified (improved) by the improver and the improvement method according to the present invention may be of any kind, and even clay or silt which has been conventionally difficult to reuse can be used as an improved soil.
For example, "Manual for Construction Site Use Technology" (1994)
Year, issued by the Japan Civil Engineering Research Center), solidified material that does not correspond to construction sludge, that is, it can be transported by truck, for example, solidified material that allows humans to walk on it, more preferably It is possible to obtain a solidified product having sufficient strength and a fine particle size having a predetermined particle size.

As the above-mentioned wet soil, specifically, for example, the soil generated at the time of excavation in the excavation work employing the underground continuous wall method, the muddy water shield method or the like is separated into earth and sand and muddy water. Sludge obtained as a dewatered cake, etc. after dewatering press by dewatering press etc .; muddy water generated during construction work is left in a sedimentation tank, sludge obtained as sediment; excavated soil, soft soil Sludge such as hydrated stone powder generated in quarries and quarries.

The hydrated soil is JIS A 1203
(Water content (g))
/ Solid content (g)) x 100 "is 20% to 2
Those within the range of 00% are preferred. A water-containing soil having a water content of more than 200% has a large water content (hereinafter referred to as "moisture content"), so that a large amount of the improver must be used, and the cost of the improver increases, which is not preferable.

The source of the hydrated soil is not particularly limited, and the hydrated soil may contain bentonite in addition to clay and silt.

The improving agent and the improving method according to the present invention include:
As described above, the present invention can be applied irrespective of the source of the hydrated soil. Among them, it is particularly suitable for the hydrated soil generated in the Kanto region. According to the survey of construction by-products, the amount of construction waste generated by the Kanto Regional Construction Bureau is highest in Japan. However, construction-generated soil generated in the Kanto region generally contains a large amount of Kanto loam (volcanic ash clay), silt, clay, and the like, and is difficult to solidify into granules. Therefore, while the reuse of hydrous soil containing generated soil generated in the Kanto region is considered desperate, according to the present invention, conventionally, it is difficult to solidify into granular form, the hydrous soil generated in the Kanto region, It can be a solidified product which is finely divided into particles having high strength and a predetermined particle diameter.

The polymer used as the improver for hydrous soil of the present invention is a polymer obtained by polymerizing a monomer component having a weight average molecular weight of more than 5,000,000 and having a carboxyl group-containing monomer in an amount of 85 mol% or more. It is.

The above-mentioned polymer can be prepared by using the above-mentioned carboxyl group-containing monomer alone or with another monomer copolymerizable with the carboxyl group-containing monomer (hereinafter simply referred to as other monomer). (Described below) can be easily obtained. That is, the monomer component contains a carboxyl group-containing monomer alone, or contains the carboxyl group-containing monomer and another monomer.

The carboxyl group-containing monomer is not particularly limited as long as it has a carboxyl group. Specific examples of the carboxyl group-containing monomer include, for example, acrylic acid, methacrylic acid, crotonic acid, vinyl acetic acid, maleic acid, itaconic acid, mesaconic acid, fumaric acid, citraconic acid, N- (meth) acryloyl asparagine Examples include acids and alkali metal salts and ammonium salts of these monomers. These monomers are
Only one type may be used, or two or more types may be used in combination. Among the above exemplified monomers, (meth) acrylic acid and / or a salt thereof are more preferable, and it is particularly preferable to use (meth) acrylic acid alone.

The other monomer is not particularly limited as long as it is a monomer copolymerizable with the carboxyl group-containing monomer. That is, the structural units other than the carboxyl group-containing monomer units that constitute the polymer according to the present invention are not particularly limited. As other monomers, specifically, for example, 2-acrylamide
-2-methylpropanesulfonic acid, (meth) allylsulfonic acid, allyloxybenzenesulfonic acid, 2-hydroxy
-3- (2-propenyloxy) propanesulfonic acid, isopropenylsulfonic acid, styrenesulfonic acid, vinylsulfonic acid, allylphosphonic acid, isopropenylphosphonic acid, vinylphosphonic acid, sulfoethyl (meth) acrylate, sulfonated isoprene, And monoethylenically unsaturated acids such as alkali metal salts and ammonium salts of these monomers; polyalkylene glycols such as polyethylene glycol (meth) acrylate and methoxypolyethylene glycol (meth) acrylate; Esters with the body; methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate,
(Meth) acrylic esters such as hydroxyethyl (meth) acrylate and hydroxypropyl (meth) acrylate; vinyl esters such as vinyl acetate, vinyl propionate, vinyl pivalate, vinyl benzoate and vinyl cinnamate; methyl vinyl ether, ethyl vinyl ether Alkyl vinyl ethers such as allyl alcohol, methallyl alcohol, 3-methyl-3-buten-1-ol, 3-methyl-2-buten-1-ol and 2-methyl-3-buten-2-ol; Aldehyde group-containing vinyl monomers such as acrolein; nitrile group-containing vinyl monomers such as (meth) acrylonitrile; (meth) acrylamide;
Monomers containing other functional groups, such as Nt-butylacrylamide, phosphoethyl methacrylate, styrene, ethylene oxide adduct of allyl alcohol, N-vinyl-2-pyrrolidone, N-vinylacetamide, N-vinylformamide; And the like. One of these other monomers may be used alone, or two or more thereof may be used in combination. Among the other monomers exemplified above, 2-acrylamido-2-methylpropanesulfonic acid, sulfoethyl (meth) acrylate, methyl (meth) acrylate, hydroxyethyl (meth) acrylate, and
N-vinyl-2-pyrrolidone is particularly preferred.

In the present invention, the ratio of the carboxyl group-containing monomer in the monomer component, that is, the ratio of the carboxyl group-containing monomer unit to all the monomer units constituting the polymer is , 85 mol% or more, more preferably 90 mol% or more, and 10 mol% or more.
Most preferably, it is 0 mol%. If the proportion of the carboxyl group-containing monomer is less than 85 mol%, it is not preferable because the improved hydrous soil cannot be granulated.

The method for producing the polymer, that is, the method for polymerizing the monomer component is not particularly limited, and includes, for example, a polymerization method using a polymerization initiator such as a radical polymerization initiator; Conventionally known various methods such as a polymerization method of irradiating radiation such as rays or ultraviolet rays; a polymerization method of heating; and the like can be employed.

As the radical polymerization initiator, peroxide-based, redox-based, or azo-based initiators can be used. Specifically, for example, ammonium persulfate, potassium persulfate, hydrogen peroxide, peroxides Peroxides, such as benzoyl and t-butyl peroxide, which are suitably used in peroxides and redox systems; sodium bisulfite, sodium metabisulfite, ammonium ferrous sulfate, L-ascorbic acid, triethanolamine, etc. 2,2'-azobis (2,4-dimethylvaleronitrile), 2,2'-azobis (2-aminopropane)
Dihydrochloride, 2,2'-azobisisobutylamide dihydrate,
Azo initiators such as 2,2′-azobis [2- (2-imidazolin-2-yl) propane] dihydrochloride; and the like, but are not particularly limited. The amount of the polymerization initiator used and the reaction conditions for the polymerization reaction are not particularly limited.

In the present invention, the weight average molecular weight of the obtained polymer needs to be larger than 5,000,000, and more preferably larger than 6,000,000. That is, the polymer of the present invention is particularly preferably sodium polyacrylate having a weight average molecular weight of 6,000,000 or more and containing free carboxyl groups of 60 mol% or more.

The above polymer has a weight average molecular weight of 5,000,000
If it is less than 10%, the improved hydrous soil cannot be granulated, which is not preferable. As a result of examination by the present inventors, hydrous soil generated in the Kanto region, when the weight average molecular weight of the polymer is small, specifically, 5,000,
When the molecular weight is less than 000, granulation does not occur. On the other hand, as the weight average molecular weight is larger, the amount of the polymer required for granulation can be reduced. Further, as a result of further study by the present inventors, if the amount of the polymer used is equal, the larger the weight-average molecular weight of the polymer is, the more improved the hydrous soil, that is, the solidified product of the hydrous soil is industrial waste. It was found that the particles could be made finer (the particle size could be reduced) within a range that did not conform to the provisions of the product.

In the present invention, the weight average molecular weight of the polymer is not particularly limited as long as it is larger than 5,000,000, but when it exceeds 20,000,000, it increases when the polymer is mixed with hydrous soil. A viscous effect may be caused to make it impossible to mix the two uniformly, and it is difficult to produce the polymer. For this reason, the upper limit of the weight average molecular weight of the polymer is not particularly limited, but is preferably substantially 20,000,000 or less.

The carboxyl group contained in the above-mentioned polymer, that is, the carboxyl group of the carboxyl-containing monomer constituting the above-mentioned polymer may be present in any form of a free acid or a salt. However, it is more preferable that a free carboxyl group is contained. Specific examples of the above salts include alkali metal salts such as sodium salt and potassium salt; alkaline earth metal salts such as calcium salt and magnesium salt; ammonium salt; amine salt; However, there is no particular limitation.

Of the carboxyl groups contained in the polymer, the ratio of free carboxyl groups is 10 mol%
It is preferably at least 20 mol%, more preferably at least 20 mol%, particularly preferably at least 40 mol%, most preferably at least 60 mol%. When the ratio of the free carboxyl groups is less than 10 mol%,
If the neutralization ratio of the above polymer exceeds 90 mol%, the improved hydrous soil may not be able to be refined. When the hydrous soil to be improved is a hydrous soil generated (discharged) in the Kanto region, a polymer in which all carboxyl groups contained in the polymer are free carboxyl groups is used as the polymer. Most preferred.

The above polymer may be used as an aqueous solution or emulsion, or may be used as a powder. However, since the aqueous solution of the polymer has a high viscosity, it has a thickening effect when mixed with water-containing soil. Occurs. For this reason, from the viewpoints of handleability and mixing properties, it is more preferable that the polymer is used as a powder by drying and pulverizing as necessary. Incidentally, the drying method and the pulverizing method of the polymer,
There is no particular limitation.

In the present invention, the viscosity of a 0.2% by weight aqueous solution of the above polymer used as a modifier for hydrous soil is 10 cp.
s or more, more preferably 20 cps or more, even more preferably
It is 50cps or more. That is, the polymer used as a modifier for hydrous soil in the present invention is a polymer having a carboxyl group and a 0.2% by weight aqueous solution having a viscosity of 10 cps or more. The viscosity of a 0.2% by weight aqueous solution of the above polymer is 10 cps
If less than, the weight average molecular weight of the polymer is, for example, 5,000
If it is larger than 000, it is not preferable because it may become impossible to granulate the improved hydrous soil, particularly the hydrous soil generated in the Kanto region. The viscosity of a 0.2% by weight aqueous solution of the above polymer may be not less than 10 cps, and the upper limit is not particularly limited. However, considering workability, it is more preferably not more than 10,000 cps, and not more than 5,000 cps.
It is more preferably at most ps, particularly preferably at most 2,000 cps.

When the above polymer is used as a powder (particle), the particle size of the polymer is preferably in the range of 0.01 mm to 2 mm, more preferably in the range of 0.02 mm to 1 mm.
If the particle size of the polymer exceeds 2 mm, the amount of the polymer required to make the solidified product finer must be increased, which increases the cost, which is not preferable. On the other hand, when the particle size of the polymer is less than 0.01 mm, dust is easily generated when the polymer is handled, and the polymer is easily absorbed by moisture. Accordingly, workability is reduced, and when added to hydrous soil, flour is generated. For this reason, in order to finely solidify the solid obtained by improving the hydrous soil, the amount of use must be increased, which increases the cost, which is not preferable.

The amount of the polymer to be used is preferably in the range of 0.01 part by weight to 5 parts by weight based on 100 parts by weight of hydrous soil.
More preferably, it is in the range of 0.01 part by weight to 1 part by weight. If the amount of the polymer is less than 0.01 part by weight, it is not preferable because the solidified product of the hydrous soil cannot be finely divided. Further, even when the amount of the polymer used is more than 5 parts by weight, the effect is almost the same as when the polymer is used within the above range. Accordingly, an excessively used polymer is wasted, which is not preferable. When the polymer is used in the form of an aqueous solution, the amount of the polymer used indicates the amount (pure content) of the polymer in the aqueous solution.

As described above, the improver for hydrous soil according to the present invention comprises a polymer having predetermined properties and the like. Next, an improvement method for improving water-containing soil using the improver having the above-described configuration will be described below.

In the improvement method according to the present invention, by mixing the above-mentioned improver (that is, the above-mentioned polymer) with the hydrated soil, the soil can be transported as an improved soil by truck. It is possible to obtain a solidified material that can be walked on by a person, and more preferably a solidified material having sufficient strength and a predetermined particle diameter, which is finely divided into particles. As a mixer used when mixing the hydrated soil and the above-mentioned improver, a device capable of stirring and mixing without kneading the mixture of both is preferable, for example, a so-called planetary motion type or a biaxial type. In addition, a device in which the shape of the stirring blade is formed in a rod shape, a fishing hook shape, or the like is preferable so that the mixture of the two can be stirred while applying a shearing force. In other words, the shape of the stirring blade, which expands in the direction perpendicular to the moving direction of the mixture that is moved by stirring and mixing as much as possible, can suppress coarsening of the particle diameter due to kneading, and can be applied to the stirring blade and the inner wall of the device. Is preferable because the adhesion of the mixture can be prevented.

Examples of such an apparatus include a horizontal axis type mixer and a vertical axis type mixer. As the horizontal shaft type mixer, for example, a single-shaft and multi-shaft paddle-type mixer is preferable. As the vertical axis 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 further preferable. While mixing the hydrated soil and the improver using the above mixer, and using the shearing force generated by the stirring blade, the mixture has a particle size in the range of 0.1 mm to 50 mm, preferably in the range of 0.3 mm to 10 mm. It can be refined (granularly solidified) into particles inside. The method of mixing the hydrated soil with the improver is not particularly limited.

Next, if necessary, a hydraulic substance is added to the obtained improved soil (granulated solidified material) and mixed. In addition, if the hydraulic substance is mixed before mixing the improver with the hydrous soil,
The hydrated soil cannot be solidified granularly.

The hydraulic substance is not particularly limited as long as it is a substance that hardens in water, and specific examples thereof include cement, quick lime, slaked lime,
Gypsum, and mixtures thereof. Among the hydraulic materials exemplified above, cement and quicklime are more preferred.

As the above cement, various known cements can be used. Specific examples of the cement include Portland cement such as ordinary Portland cement, early-strength Portland cement, and ultra-high-strength Portland cement; blast furnace cement; alumina cement; calcium cement; fly ash cement; There is no particular limitation.

The amount of the hydraulic substance to be used is preferably in the range of 1 part by weight to 35 parts by weight, more preferably in the range of 1 part by weight to 20 parts by weight, and more preferably in the range of 1 part by weight to 10 parts by weight based on 100 parts by weight of the hydrated soil. More preferably, it is in the range of parts by weight. If the amount of the hydraulic substance used is less than 1 part by weight, the strength (described later) of the improved soil (granulated solidified material) may be insufficient. Further, even when the amount of the hydraulic substance used is more than 35 parts by weight, the effect is almost the same as when the hydraulic substance is used within the above range. Therefore, an excessively used hydraulic substance is wasted, which is not preferable.

The mixer used for mixing the hydraulic material with the improved soil (granular solidified material) is not particularly limited, but an apparatus capable of stirring and mixing the two without kneading the mixture. Is preferred. In addition, when mixing using such a mixer, the shearing force is not applied as much as when mixing the above-mentioned hydrated soil and the improver, and a hydraulic substance is attached to the surface of the improved soil (granulated solidified material). It is preferable to stir so as to glaze. As a result, an improved soil (granulated solid) in which the hydraulic substance adheres almost uniformly to the surface of the improved soil (granulated solid) is obtained. In addition, the hydraulic substance may partially enter the inside of the improved soil (granular solidified material). Further, the method of mixing the improved soil (granular solidified material) and the hydraulic substance is not particularly limited.

The resulting improved soil (granulated solidified material) may be immediately backfilled, but if left at room temperature for about 3 to 7 days, the hydraulic substance is cured, so that a predetermined strength is obtained. Can be prepared.

The improved soil obtained as described above can be transported by truck, and is, for example, a solidified material improved so that a person can walk on it, more preferably a granular solidified material. Therefore, the improved soil does not correspond to industrial waste and can be reused. In particular, granular solids
Since it has a predetermined particle size and strength, it can be reused as a resource such as a substitute for sand without performing operations such as crushing and sieving. That is, in civil engineering work in which excavation holes need to be backfilled, backfill can be performed using the granular solidified material without separately preparing sand or the like. In addition, since the granular solidified material can improve water permeability when backfilled on the ground, it is possible to reuse the hydrous soil in a wider range. The particulate solidified material is, for example, a backfill material for backfilling a buried pipe or a structure, a barrier layer material as artificial sand, a vegetation base material for spraying a slope to process the slope, a soil improvement material , A water retaining material, a water permeable material, a water quality improving material, and the like. As described above, the use of the improving agent and the improving method of the present invention makes it possible to reuse hydrated soil that is usually discarded as sludge, so that environmental conservation, resource saving, and life extension of disposal sites can be achieved. At the same time, the disposal cost of hydrous soil can be reduced.

[0047]

The present invention will be described in more detail with reference to the following Examples and Comparative Examples, but the present invention is not limited thereto. The weight average molecular weight (Mw) of the polymer as an improving agent was measured by gel permeation chromatography (GPC). In addition, 0.2 of the polymer
The viscosity of the weight% aqueous solution was measured at 25 ° C. using a B-type viscometer.

[Example 1] The muddy water generated by the excavation work employing the muddy water shield method in the Kanto region was dewatered and pressed to obtain a hydrous soil. The water content of the water-containing soil was 62% by weight.

Next, a predetermined amount of the above-mentioned hydrated soil was charged into a planetary mixer (planetary mixer) provided with a hook-type stirring blade in the shape of a fishing hook. Subsequently, while the hydrous soil was stirred at 160 rpm, a powdery partially neutralized product of polyacrylic acid with sodium hydroxide (A) (hereinafter referred to as “polystyrene”) as an improver according to the present invention was added to the hydrous soil. Acrylic acid partially neutralized product (A)) was added and mixed little by little so that the ratio to the above-mentioned hydrous soil was 0.05% by weight.

The neutralization rate of the partially neutralized polyacrylic acid (A) is 30 mol%, the weight average molecular weight (Mw) is 6,000,000, the particle diameter is in the range of 0.05 mm to 0.25 mm, and the viscosity of the 0.2 wt% aqueous solution is Was 90 cps, and the ratio of the carboxyl group-containing monomer in the monomer component was 100 mol%.

As a result, a finely divided product having a particle diameter in the range of 0.5 mm to 5 mm and an average particle diameter of 2 mm was obtained. afterwards,
The finely divided product was left at room temperature for 7 days to obtain a granular solidified product. Table 1 shows the main solidification conditions and the particle size of the finely divided material.
Shown in

[Example 2] The muddy water of Example 1 was dewatered and pressed in the same mixer as in Example 1 to obtain a water content of 1
A predetermined amount of 48% hydrous soil was charged. Subsequently, while stirring the hydrous soil at 160 rpm, the powdery polyacrylic acid partially neutralized product (A) was gradually added to the hydrous soil so that the ratio to the hydrous soil was 0.08% by weight. The mixture was added and mixed to obtain a granular material. Next, the obtained granules were reduced to 160 rpm.
While stirring, Portland cement as a hydraulic substance was added to the granules at a ratio of 3 to the above-mentioned hydrous soil.
It was added and mixed little by little so as to become the weight%.

As a result, a finely divided product having a particle diameter in the range of 0.5 mm to 10 mm and an average particle diameter of 3 mm was obtained. afterwards,
The finely divided product was left at room temperature for 7 days to obtain a granular solidified product. Table 1 shows the main solidification conditions and the particle size of the finely divided material.
Shown in

Example 3 The same water content as that of Example 1 was obtained by pressing the muddy water of Example 1 by dewatering press.
A predetermined amount of 48% hydrous soil was charged. Subsequently, while stirring the hydrous soil at 160 rpm, a partially neutralized product of a powdery acrylic acid / methacrylic acid copolymer (B) as a modifier according to the present invention with sodium hydroxide was added to the hydrous soil. )
(Hereinafter referred to as a partially neutralized product of acrylic acid / methacrylic acid copolymer (B)) with a ratio of 0.1 to the hydrous soil.
It was added and mixed little by little so as to become the weight%.

The molar ratio of acrylic acid to methacrylic acid in the partially neutralized acrylic acid / methacrylic acid copolymer (B) is 60/40, and the carboxyl group-containing monomer The ratio is 100 mol%, the neutralization ratio of the partially neutralized acrylic acid / methacrylic acid copolymer (B) is 40 mol%, the weight average molecular weight (Mw) is 8,000,000, and the particle diameter is 0.01 mm to 2 mm. Within the range, the viscosity of the 0.2% by weight aqueous solution is 1
10 cps.

As a result, a finely divided product having a particle diameter in the range of 1 mm to 10 mm and an average particle diameter of 2 mm was obtained. Thereafter, the finely divided product was left at room temperature for 7 days to obtain a granular solidified product.
Table 1 shows the main solidification conditions, the particle size of the finely divided material, and the like.

Example 4 The same mixer as that of Example 1 was used to dewater and press the muddy water of Example 1 to obtain a water content ratio of 62.
% Of hydrous soil was charged in a predetermined amount. Subsequently, the hydrous soil is
While stirring at 160 rpm, the powdery partially neutralized product of the acrylic acid / methacrylic acid copolymer (B) was added to the water-containing soil.
Was added little by little so that the ratio to the above-mentioned hydrous soil was 0.1% by weight, and mixed to obtain a granular material. Next, while the obtained granules were stirred at 160 rpm, quicklime as a hydraulic substance was added to the granules little by little so that the ratio to the above-mentioned hydrous soil was 6% by weight.

As a result, a finely divided product having a particle size in the range of 2 mm to 20 mm and an average particle size of 4 mm was obtained. Thereafter, the finely divided product was left at room temperature for 7 days to obtain a granular solidified product.
Table 1 shows the main solidification conditions, the particle size of the finely divided material, and the like.

[0059]

[Table 1]

Example 5 The same mixer as that of Example 1 was used to dewater and press the muddy water of Example 1 to obtain a water content of 1
A predetermined amount of 48% hydrous soil was charged. Subsequently, while stirring the hydrous soil at 160 rpm, a powdery partially neutralized product of polyacrylic acid with sodium hydroxide (C) (hereinafter referred to as “polystyrene”) as an improver according to the present invention was added to the hydrous soil while stirring. Acrylic acid partially neutralized product (C)) was added and mixed little by little so that the ratio with respect to the hydrous soil was 0.05% by weight.

The neutralization rate of the partially neutralized polyacrylic acid (C) is 20 mol%, the weight average molecular weight (Mw) is 5,500,000, the particle size is in the range of 0.02 mm to 2 mm, and the viscosity of the 0.2 wt% aqueous solution is It was 50 cps, and the ratio of the carboxyl group-containing monomer in the monomer component was 100 mol%.

As a result, a finely divided product having a particle diameter in the range of 0.5 mm to 10 mm and an average particle diameter of 3 mm was obtained. afterwards,
The finely divided product was left at room temperature for 7 days to obtain a granular solidified product. Table 2 shows the main solidification conditions and the particle size of the finely divided material.
Shown in

Example 6 The same mixer as that of Example 1 was used, and the muddy water of Example 1 was dewatered and pressed to obtain a water content ratio of 1
A predetermined amount of 48% hydrous soil was charged. Subsequently, while stirring the hydrous soil at 160 rpm, the powdery partially neutralized polyacrylic acid (C) was gradually added to the hydrous soil such that the ratio to the hydrous soil was 0.1% by weight. The mixture was added and mixed to obtain a granular material. Next, the obtained granules were reduced to 160 rpm.
While stirring with, blast furnace cement as a hydraulic substance was gradually added to and mixed with the granules so that the ratio to the above-mentioned hydrous soil was 1% by weight.

As a result, a finely divided product having a particle diameter in the range of 0.5 mm to 5 mm and an average particle diameter of 1 mm was obtained. afterwards,
The finely divided product was left at room temperature for 7 days to obtain a granular solidified product. Table 2 shows the main solidification conditions and the particle size of the finely divided material.
Shown in

Example 7 The same mixer as in Example 1 was subjected to dewatering press of the muddy water of Example 1 to obtain a water content ratio of 1
A predetermined amount of 08% hydrous soil was charged. Subsequently, while stirring the hydrous soil at 160 rpm, a partially neutralized product (D) of a powdery acrylic acid / methacrylic acid copolymer as a modifier according to the present invention with sodium hydroxide was added to the hydrous soil. )
(Hereinafter, referred to as a partially neutralized product of acrylic acid / methacrylic acid copolymer (D)) in a ratio of 0.1 to the hydrous soil.
The mixture was added little by little so as to obtain a weight percentage, and a granular material was obtained.

The molar ratio of acrylic acid to methacrylic acid in the partially neutralized product of acrylic acid / methacrylic acid copolymer (D) is 50/50, and the carboxyl group-containing monomer in the monomer component The ratio is 100 mol%, the neutralization ratio of the partially neutralized acrylic acid / methacrylic acid copolymer (D) is 50 mol%, the weight average molecular weight (Mw) is 6,500,000, and the particle diameter is 0.02 mm to 1 mm. , The viscosity of the 0.2% by weight aqueous solution is 2
It was 50 cps.

While stirring the obtained granules at 160 rpm, Portland cement as a hydraulic substance was added to the granules little by little so that the ratio to the above-mentioned hydrous soil was 3% by weight. .

As a result, a finely divided product having a particle diameter in the range of 3 mm to 15 mm and an average particle diameter of 4 mm was obtained. Thereafter, the finely divided product was left at room temperature for 7 days to obtain a granular solidified product.
Table 2 shows the main solidification conditions, the particle size of the finely divided material, and the like.

Example 8 The same mixer as in Example 1 was prepared by dewatering and pressing the muddy water of Example 1 with a water content ratio of 1
A predetermined amount of 08% hydrous soil was charged. Subsequently, while stirring the water-containing soil at 160 rpm, the powdery acrylic acid / methyl acrylate copolymer (E) as the improver according to the present invention was added to the water-containing soil at a ratio to the water-containing soil.
Granules were obtained by adding and mixing little by little so as to be 0.2% by weight.

In the acrylic acid / methyl acrylate copolymer (E), the molar ratio between acrylic acid and methyl acrylate is 90/10, and the ratio of the carboxyl group-containing monomer in the monomer component is 90 mol%. The neutralization ratio of the acrylic acid / methyl acrylate copolymer (E) is 0 mol%, the weight average molecular weight (Mw) is 10,000,000, and the particle diameter is 0.01 mm.
Within a range of ２2 mm, the viscosity of the 0.2% by weight aqueous solution was 100 cps.

While stirring the obtained granules at 160 rpm, fly ash as a hydraulic substance was added to the granules little by little so that the ratio to the above-mentioned hydrous soil was 3% by weight. .

As a result, a finely divided product having a particle diameter in the range of 3 mm to 20 mm and an average particle diameter of 5 mm was obtained. Thereafter, the finely divided product was left at room temperature for 7 days to obtain a granular solidified product.
Table 2 shows the main solidification conditions, the particle size of the finely divided material, and the like.

[0073]

[Table 2]

Example 9 The same mixer as that of Example 1 was used, and the muddy water of Example 1 was dewatered and pressed to obtain a water content ratio of 1
A predetermined amount of 08% hydrous soil was charged. Subsequently, while stirring the water-containing soil at 160 rpm, a powdery sodium acrylic acid / 2-acrylamido-2-methylpropanesulfonate copolymer (F) as an improver according to the present invention was added to the water-containing soil. Was added little by little so that the ratio to the above-mentioned hydrous soil was 0.1% by weight, and mixed to obtain a granular material.

The molar ratio of acrylic acid to sodium 2-acrylamido-2-methylpropanesulfonate in the acrylic acid / 2-acrylamido-2-methylpropanesulfonate copolymer (F) is 90/10, 90 mol% of carboxyl group-containing monomer in the monomer component
The acrylic acid / 2-acrylamido-2-methylpropanesulfonic acid sodium copolymer (F) has a carboxyl group neutralization ratio of 10 mol% and a weight average molecular weight (Mw) of
7,000,000, the particle size was in the range of 0.05 mm to 1 mm, and the viscosity of the 0.2% by weight aqueous solution was 150 cps.

While the obtained granules were stirred at 160 rpm, slaked lime as a hydraulic substance was added to the granules little by little so that the ratio to the above-mentioned hydrous soil was 3% by weight.

As a result, a finely divided product having a particle diameter in the range of 0.5 mm to 5 mm and an average particle diameter of 3 mm was obtained. afterwards,
The finely divided product was left at room temperature for 7 days to obtain a granular solidified product. Table 3 shows the main solidification conditions and the particle size of the finely divided material.
Shown in

[Example 10] The water content of the same mixer as in Example 1 was obtained by dewatering and pressing the muddy water of Example 1
A predetermined amount of 148% hydrous soil was charged. Subsequently, while stirring the hydrous soil at 160 rpm, powdery sodium acrylate as an improver according to the present invention was added to the hydrous soil.
The N-vinyl-2-pyrrolidone copolymer (G) was added and mixed little by little so that the ratio with respect to the water-containing soil was 0.1% by weight, to obtain a granular material.

The above sodium acrylate / N-vinyl-2-
The molar ratio of sodium acrylate to N-vinyl-2-pyrrolidone in the pyrrolidone copolymer (G) is 85/15, and the ratio of the carboxyl group-containing monomer in the monomer component is
85 mol%, the above sodium acrylate / N-vinyl
The 2-pyrrolidone copolymer (G) has a neutralization ratio of 90 mol%, a weight average molecular weight (Mw) of 6,000,000, and a particle size of 0.05 mm to 1 mm.
Within the range, the viscosity of the 0.2% by weight aqueous solution was 350 cps.

As a result, a finely divided product having a particle diameter in the range of 1 mm to 10 mm and an average particle diameter of 4 mm was obtained. Thereafter, the finely divided product was left at room temperature for 7 days to obtain a granular solidified product.
Table 3 shows the main solidification conditions, the particle size of the finely divided product, and the like.

Example 11 The same water content as that of Example 1 was obtained by dewatering and pressing the muddy water of Example 1
A predetermined amount of 148% hydrous soil was charged. Subsequently, while stirring the hydrated soil at 160 rpm, the powdery methacrylic acid / hydroxyethyl methacrylate copolymer (H) as an improver according to the present invention was added to the hydrated soil at a ratio relative to the hydrated soil. Granules were obtained by adding and mixing little by little so as to become 0.3% by weight.

The molar ratio of methacrylic acid to hydroxyethyl methacrylate in the methacrylic acid / hydroxyethyl methacrylate copolymer (H) is 95/5,
The proportion of the carboxyl group-containing monomer in the monomer component was 95 mol%, the neutralization ratio of the methacrylic acid / hydroxyethyl methacrylate copolymer (H) was 100 mol%, and the weight average molecular weight (Mw) was 5,500,000, the particle diameter was in the range of 0.05 mm to 1 mm, and the viscosity of the 0.2% by weight aqueous solution was 180 cps.

While stirring the obtained granules at 160 rpm, Portland cement as a hydraulic substance was added to the granules little by little so that the ratio to the above-mentioned hydrous soil was 5% by weight. .

As a result, a finely divided product having a particle diameter in the range of 0.5 mm to 20 mm and an average particle diameter of 4 mm was obtained. afterwards,
The finely divided product was left at room temperature for 7 days to obtain a granular solidified product. Table 3 shows the main solidification conditions and the particle size of the finely divided material.
Shown in

[0085]

[Table 3]

[Comparative Example 1] The same mixer as that of Example 1 was subjected to dewatering press of the muddy water of Example 1 to obtain a water content of 62.
% Of hydrous soil was charged in a predetermined amount. Subsequently, the hydrous soil is
While stirring at 160 rpm, a partially neutralized product of a powdery acrylic acid / methacrylic acid copolymer with sodium hydroxide (J) (hereinafter referred to as “J”) was added to the hydrous soil as a modifier for comparison.
Partially neutralized acrylic acid / methacrylic acid copolymer (J)
) Was added little by little so that the ratio to the above-mentioned hydrous soil was 0.2% by weight, and mixed to obtain a granular material.

The molar ratio of acrylic acid to methacrylic acid in the above partially neutralized acrylic acid / methacrylic acid copolymer (J) is 70/30, and the carboxyl group-containing monomer The ratio is 100 mol%, the neutralization ratio of the partially neutralized acrylic acid / methacrylic acid copolymer (J) is 30 mol%, the weight average molecular weight (Mw) is 2,000,000, and the particle diameter is 0.02 mm to 2 mm. And the viscosity of the 0.2% by weight aqueous solution is 8
cps.

Thereafter, while stirring the obtained granules at 160 rpm, Portland cement as a hydraulic substance was added to the granules at a ratio of 3% by weight to the above-mentioned hydrous soil.
Was added and mixed little by little so that However,
No granules could be obtained. Table 4 shows the main solidification conditions.
Shown in

[Comparative Example 2] The muddy water of Example 1 was dewatered and pressed in the same mixer as in Example 1 to obtain a water content of 1
A predetermined amount of 08% hydrous soil was charged. Subsequently, while stirring the hydrous soil at 160 rpm, a powdery sodium polyacrylate (K) as a comparative improver was added to the hydrous soil.
Was added little by little so that the ratio to the above-mentioned hydrated soil was 0.2% by weight, and mixed to obtain a granular material.

The neutralization rate of the sodium polyacrylate (K) is 100 mol%, the weight average molecular weight (Mw) is 2,000,000,
The particle diameter was in the range of 0.02 mm to 2 mm, the viscosity of the 0.2% by weight aqueous solution was 7 cps, and the ratio of the carboxyl group-containing monomer in the monomer component was 100 mol%.

Thereafter, while the obtained granules were stirred at 160 rpm, quick lime as a hydraulic substance was added to the granules.
It was added and mixed little by little so that the ratio to the above-mentioned hydrated soil was 6% by weight. However, no granular material could be obtained. Table 4 shows the main solidification conditions.

[Comparative Example 3] The muddy water of Example 1 was dewatered and pressed in the same mixer as in Example 1 to obtain a water content of 62.
% Of hydrous soil was charged in a predetermined amount. Subsequently, the hydrous soil is
While stirring at 160 rpm, a powdery sodium acrylate / methyl acrylate copolymer (L) as a modifier for comparison was slightly added to the hydrous soil so that the ratio to the hydrous soil was 0.2% by weight. Each was added and mixed.

The molar ratio between sodium acrylate and methyl acrylate in the sodium acrylate / methyl acrylate copolymer (L) is 80/20, and the ratio of the carboxyl group-containing monomer in the monomer component is 80/20. Mol%, the neutralization ratio of the sodium acrylate / methyl acrylate copolymer (L) was 80 mol%, and the weight average molecular weight (M
w) is 1,000,000, particle size is in the range of 0.02mm ~ 2mm, 0.2
The viscosity of the weight% aqueous solution was 5 cps.

However, no granular material could be obtained. Table 4 shows the main solidification conditions.

[0095]

[Table 4]

From the results shown in Tables 1 to 3, it is understood that the use of the improver according to the present invention can make the above-mentioned hydrous soil finer. From the results shown in Table 4, if the proportion of the carboxyl group-containing monomer in the monomer component is less than 85 mol% or the weight average molecular weight is less than 5,000,000, It turns out that it cannot be granulated. Further, it can be seen that if the viscosity of the modifier (polymer) in a 0.2% by weight aqueous solution is less than 10 cps, the above-mentioned hydrous soil cannot be granulated.

[0097]

As described above, the improver for hydrous soil according to claim 1 of the present invention has a monomer component having a weight average molecular weight of more than 5,000,000 and a carboxyl group-containing monomer of 85 mol% or more. Is a configuration including a polymer obtained by polymerizing As described above, the improver for hydrous soil according to claim 2 of the present invention has a configuration in which the above-mentioned polymer contains a free carboxyl group. The improver for hydrous soil according to claim 3 of the present invention has a configuration in which the carboxyl group-containing monomer is (meth) acrylic acid as described above. The improver for hydrous soil according to claim 4 of the present invention, as described above,
The above-mentioned polymer is configured to be sodium polyacrylate having a weight-average molecular weight of 6,000,000 or more and containing free carboxyl groups of 60 mol% or more. Further, the improver for hydrous soil according to claim 5 of the present invention has a structure comprising a polymer having a carboxyl group and a 0.2% by weight aqueous solution having a viscosity of 10 cps or more.

According to the above configuration, the improved hydrous soil can be transported by truck, for example, a solidified product improved to a state where a person can walk on it, and more preferably, having sufficient strength and strength. Since it can be solidified into a fine particle having a predetermined particle size, the water-containing soil normally discarded as sludge can be effectively used as a resource such as a substitute for sand (reuse). It has the effect that it can be done. In addition, since the solidified material after improvement can be reused, it is possible to save the environment, save resources, extend the life of disposal sites, and reduce the disposal cost of hydrous soil. Play.

Further, the method for improving a hydrated soil according to claim 6 of the present invention comprises, as described above, a method of mixing the hydrated soil improver according to any one of claims 1 to 5 with the hydrated soil. It is. The method for improving a hydrous soil according to claim 7 of the present invention comprises:
As described above, this is a method for improving the above-mentioned hydrous soil into granules.

According to the above-mentioned method, the improved hydrous soil can be transported by truck, for example, a solidified product improved so that a person can walk on it, more preferably, having sufficient strength and strength. Since it can be solidified into a fine particle having a predetermined particle size, the water-containing soil normally discarded as sludge can be effectively used as a resource such as a substitute for sand (reuse). It has the effect that it can be done. In addition, since the solidified material after improvement can be reused, it is possible to save the environment, save resources, extend the life of disposal sites, and reduce the disposal cost of hydrous soil. Play.

Claims (7)

[Claims] 1. A method for improving a hydrous soil, comprising a polymer obtained by polymerizing a monomer component having a weight average molecular weight of more than 5,000,000 and having a carboxyl group-containing monomer of 85 mol% or more. 2. The improver for hydrous soil according to claim 1, wherein said polymer contains a free carboxyl group. 3. The method according to claim 1, wherein the carboxyl group-containing monomer is (meth)
The improver for hydrous soil according to claim 1 or 2, which is acrylic acid. 4. The polymer according to claim 1, wherein the polymer has a free carboxyl group.
The agent for improving hydrous soil according to any one of claims 1 to 3, wherein the agent is sodium polyacrylate having a weight average molecular weight of 6,000,000 or more containing 60 mol% or more. 5. A hydrous soil improver comprising a polymer having a carboxyl group and having a 0.2% by weight aqueous solution having a viscosity of 10 cps or more. 6. A method for improving a hydrous soil, comprising mixing the hydrous soil improver according to any one of claims 1 to 5 into the hydrous soil. 7. The method for improving hydrous soil according to claim 6, wherein the hydrous soil is improved to a granular form.