JPH09241641A - Water-reducing agent for ultrahigh-pressure jet grouting construction - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject water-reducing agent, comprising a component selected from a hydroxycarboxylic acid (salt) and a specific polymer (salt) and capable of reducing the chemical oxygen demand (COD), etc., of water in waste sludges produced by an ultrahigh-pressure jet grouting construction method and facilitating the waste sludge treatment. SOLUTION: This water-reducing agent comprises one or more selected from (A) a hydroxycarboxylic acid (salt), (B) a (co)polymer (salt), comprising monomers selected from acrylic acid, methacrylic acid, vinyl acetate, etc., and respectively having 1000-500000 weight-average molecular weight, (C) a copolymer (salt) comprising monomers selected from (i) acrylic acid and/or methacrylic acid and (ii) an alkyl acrylate having a 1-8C alkyl group, styrene, etc., (D) a copolymer (salt) comprising the component (i) and (iii) an unsaturated dicarboxylic acid selected from maleic acid, fumaric acid, etc., and (E) a copolymer (salt) comprising (iv) an unsaturated carboxylic acid selected from acrylic acid, maleic anhydride, etc., and (v) an unsaturated sulfonic acid such as styrenesulfonic acid and vinylsulfonic acid.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water reducing agent useful for an ultrahigh pressure jet injection method for improving the ground by utilizing an ultrahigh pressure jet liquid (jet).

[0002]

2. Description of the Related Art Conventionally, various ultra-high pressure jet injection methods using ultra-high-pressure jet liquid (jet) have been widely used as ground improvement methods for the purpose of improving soft ground and building foundations for buildings. It is used.

Although these construction methods are different in the presence or absence of combined use of air, the cutting method, the discharge method of sludge (slime), etc., basically, a super-high pressure fluid is jetted and the energy of the jet flow is used to scavenge the ground. Along with cutting and breaking, a hardened material is formed by injecting and filling a hardened material into the space generated by this cutting and breaking, and there are few application restrictions due to the soil quality of the ground, and a homogeneous solidified body can be formed. It has excellent features such as almost no effect on existing buried objects.

By the way, in such an ultra-high pressure jet injection method, a water reducing agent is usually used together with cement. Due to this water reducing agent, CO contained in the sludge is removed.
There is a problem that D and BOD become high and the processing is difficult.

That is, conventionally, the sludge discharged during the construction of the super-high pressure jet injection method is generally treated by separating it with water such as by applying it to a filter press or the like. However, the water generated at this time contains a water reducing agent, and conventional water reducing agents have high COD and BOD. Therefore, if they are directly discharged into a river or the sea, they will be contaminated. There was a risk of

[0006]

As described above, the super-high pressure jet injection method is widely used as a ground improvement method because it has various excellent characteristics. However, COD, which is a water-reducing agent compounded in a hardening material, is used. There is a problem that it is difficult to treat the sludge due to high BOD and BOD.

The present invention has been made to solve the above problems, and is a highly safe water reducing agent that facilitates the treatment of sludge generated in an ultrahigh pressure jet injection method and an ultrahigh pressure using the same. It is intended to provide a jet injection method.

[0008]

As a result of intensive studies conducted by the present inventors in order to achieve the above object, as a result, an oxycarboxylic acid or a salt thereof, or a polymer of a certain kind or a salt thereof was used as a super-high pressure jet injection method. The present invention has been completed as a result of finding that it has an excellent effect as a water-reducing agent for water, and further finding out that the combined use thereof has a more excellent effect.

That is, the present invention provides (A) an oxycarboxylic acid or a salt thereof, (B) acrylic acid, methacrylic acid,
1 or 2 selected from vinyl acetic acid and crotonic acid
Homopolymers, copolymers, produced from more than one monomer
Or a salt thereof having a weight average molecular weight of 1,000 to
500,000, (C) (a) acrylic acid and /
Or methacrylic acid and (b) alkyl group has 1 carbon atom
~ 8 acrylic acid alkyl ester, alkyl group having 1-8 carbon atoms of methacrylic acid, alkyl group having 1-8 carbon atoms of hydroxyalkyl ester, alkyl group having 1-8 carbon atoms of methacrylic acid A copolymer or salt thereof formed from one or more monomers selected from acid hydroxyalkyl esters, acrylamide, styrene, isobutylene and vinyl acetate, having a weight average molecular weight of 1,000 to 500,000. Of (D) (a) acrylic acid and / or methacrylic acid and (c) one or more unsaturated dicarboxylic acids selected from maleic acid, maleic anhydride, fumaric acid and itaconic acid A copolymer or a salt thereof produced from the body, having a weight average molecular weight of 1,000 to 500,
(E) (d) one or more unsaturated carboxylic acids selected from (d) acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid and itaconic acid, and (e) styrene. Sulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid, 3-acryloxy
-2-A copolymer or salt thereof produced from one or more unsaturated sulfonic acids selected from hydroxy-propane sulfonic acid, vinyl sulfonic acid, allyl sulfonic acid and methallyl sulfonic acid, Those having a weight average molecular weight of 1,000 to 300,000, and (F) (D)
One or more unsaturated carboxylic acids selected from acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid and itaconic acid, and (e) styrenesulfonic acid, 2-acrylamido-2-methylpropane One or more unsaturated sulfonic acids selected from sulfonic acid, 3-acryloxy-2-hydroxy-propanesulfonic acid, vinylsulfonic acid, allylsulfonic acid and methallylsulfonic acid, and (b) alkyl group Has 1 carbon
~ 8 acrylic acid alkyl ester, alkyl group having 1-8 carbon atoms of methacrylic acid, alkyl group having 1-8 carbon atoms of hydroxyalkyl ester, 1-8 carbon atoms of hydroxyalkyl methacrylate A copolymer or salt thereof produced from one or more monomers selected from ester, acrylamide, styrene, vinyl acetate and isobutylene, and having a weight average molecular weight of 1,000 to 500,000. It is a water reducing agent for an ultra-high pressure jet injection method characterized by containing at least one kind.

In the present invention, in particular, the above-mentioned oxycarboxylic acid of (A) or a salt thereof and at least one selected from the polymers of (B) to (F) or a salt thereof are contained. desirable.

Hereinafter, the present invention will be described in detail. The weight average molecular weight in the present invention is gel permeation (GPC) using polyethylene glycol as a standard product.
It was measured by the method.

Preferred examples of the (A) oxycarboxylic acid include glycolic acid, hydroxypropanoic acid (eg lactic acid, 3-hydroxypropanoic acid etc.), hydroxybutyric acid (eg 2-hydroxybutyric acid, 3-hydroxy). Butyric acid, 4-
Hydroxybutyric acid, etc.), hydroxyvaleric acid (eg, 2-hydroxyvaleric acid, 3-hydroxyvaleric acid, 4-hydroxyvaleric acid, 5-hydroxyvaleric acid, etc.), glyceric acid, tartaric acid, citric acid, tartronic acid, malic acid , Citramalic acid, gluconic acid and the like, among which gluconic acid is preferred.

Examples of such oxycarboxylic acid salts include ammonium salts, alkali metal salts (eg, sodium salt, potassium salt, etc.) and alkaline earth metal salts (eg, calcium salt, magnesium salt, etc.). Named
Of these, alkali metal salts are preferable.

A preferred specific example is sodium gluconate.

(B) A homopolymer, a copolymer or a salt thereof formed from one or more monomers selected from acrylic acid, methacrylic acid, vinylacetic acid and crotonic acid. And the weight average molecular weight is 1,000 to 500,
A preferable example of 000 is a homopolymer of acrylic acid or a salt thereof having a weight average molecular weight of 1,00.
A copolymer of acrylic acid and methacrylic acid or a salt thereof having a weight average molecular weight of 1,000 to 200,000 and a polymerization ratio of acrylic acid or a salt thereof to methacrylic acid or a salt thereof in a molar ratio. 10: 90 ~
In the range of 99: 1, a homopolymer of acrylic acid having a weight average molecular weight of 5,000 to 100,000 or a salt thereof, and a weight average molecular weight of 5,0
00-10,000, the polymerization ratio of acrylic acid or a salt thereof and methacrylic acid or a salt thereof is 50:50 to 99: 1 in a molar ratio.
A copolymer consisting of acrylic acid and methacrylic acid in the range of or a salt thereof is suitable.

The salts of the above polymers include ammonium salts, alkali metal salts (eg sodium salt, potassium salt etc.), alkaline earth metal salts (eg calcium salt,
Magnesium salts and the like), and among them, alkali metal salts are preferable.

A preferred specific example is sodium polyacrylate having a weight average molecular weight of 10,000, and a weight average molecular weight of 1
00,000 sodium polyacrylate, weight average molecular weight 300,
000 polysodium acrylate, weight average molecular weight 10,000
Ammonium polyacrylate with a weight average molecular weight of 10,0
00, a copolymer of sodium acrylate and methacrylic acid in which the polymerization ratio of sodium acrylate and methacrylic acid is 70:30 in a molar ratio. In (C), (i) acrylic acid and / or methacrylic acid, and (b) the number of carbon atoms in the alkyl group is
1-8 acrylic acid alkyl ester, alkyl group having 1-8 carbon atoms of methacrylic acid, alkyl group having 1-8 carbon atoms of hydroxyalkyl ester, alkyl group having 1-8 carbon atoms A copolymer produced from one or more monomers selected from hydroxyalkyl methacrylate, acrylamide, styrene, isobutylene and vinyl acetate, or a salt thereof, having a weight average molecular weight of 1,000 to 500,000. A preferred example is a copolymer of acrylic acid and acrylamide or a salt thereof having a weight average molecular weight of 1,000 to 200,000 and a polymerization ratio of acrylic acid or a salt to acrylamide of 10:90 to 99 in a molar ratio. : 1 and the weight average molecular weight is
A copolymer or a salt thereof of acrylic acid and acrylamide having a polymerization ratio of 5,000 to 100,000 and acrylic acid or a salt thereof and acrylamide in a molar ratio of 50:50 to 99: 1 is preferable.

As a preferred specific example, a copolymer of sodium acrylate and acrylamide having a weight average molecular weight of 10,000 and a polymerization ratio of sodium acrylate and acrylamide of 90:10 in molar ratio can be mentioned.

(D) (a) acrylic acid and / or methacrylic acid, and (c) maleic acid, maleic anhydride,
1 or 2 selected from fumaric acid and itaconic acid
A copolymer produced from one or more kinds of unsaturated dicarboxylic acid monomers or a salt thereof, having a weight average molecular weight of 1,000.
As a preferable example of those having a weight average molecular weight of 1,000 to 200,000, a polymerization ratio of acrylic acid or a salt thereof and maleic acid or a salt thereof is a copolymer of acrylic acid and maleic acid or a salt thereof. In molar ratio
The weight average molecular weight is 5,000 to 100,000 and the polymerization ratio of acrylic acid or its salt to maleic acid or its salt is 80:20 in molar ratio. A copolymer of acrylic acid and maleic acid in the range of up to 99: 1 or a salt thereof is suitable.

A preferred specific example is a copolymer of sodium acrylate and sodium maleate having a weight average molecular weight of 10,000 and a polymerization ratio of sodium acrylate and sodium maleate of 95: 5 in a molar ratio. To be

(E) One or more unsaturated carboxylic acids selected from (d) acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid and itaconic acid, and (e) styrene sulfone. Acid, 2-acrylamido-2-methylpropanesulfonic acid, 3-acryloxy-2
-Hydroxy-Copolymer or salt thereof formed from one or more unsaturated sulfonic acids selected from propanesulfonic acid, vinylsulfonic acid, allylsulfonic acid and methallylsulfonic acid, and having a weight average A preferable example of the one having a molecular weight of 1,000 to 300,000 is
A copolymer of acrylic acid and styrene sulfonic acid or 2-acrylamido-2-methylpropane sulfonic acid or a salt thereof, having a weight average molecular weight of 1,000 to 200,000.
, Acrylic acid or a salt thereof and styrene sulfonic acid or a salt thereof, or 2-acrylamido-2-methylpropane sulfonic acid or a salt thereof in a molar ratio of 10:
Examples include those in the range of 90 to 99: 1. Among them, acrylic acid and styrene sulfonic acid or 2-acrylamide.
-2-Methylpropanesulfonic acid copolymer or salt thereof, having a weight average molecular weight of 5,000 to 100,000,
The polymerization ratio of acrylic acid or a salt thereof and styrenesulfonic acid or a salt thereof or 2-acrylamido-2-methylpropanesulfonic acid or a salt thereof is 10:90 by molar ratio.
The weight average molecular weight is in the range of 99: 1.
5,000 to 100,000, and the polymerization ratio of acrylic acid or its salt and styrene sulfonic acid or its salt or 2-acrylamido-2-methylpropane sulfonic acid or its salt is in the range of 50:50 to 99: 1 in molar ratio. A copolymer of acrylic acid and styrene sulfonic acid or 2-acrylamido-2-methylpropane sulfonic acid or a salt thereof is more preferable.

As a preferred specific example, a copolymer of sodium acrylate and sodium styrenesulfonate having a weight average molecular weight of 12,000 and a polymerization ratio of sodium acrylate and sodium styrenesulfonate of 70:30 in a molar ratio, and The weight average molecular weight is 15,000, and the polymerization ratio of sodium acrylate and sodium 2-acrylamido-2-methylpropane sulfonate is 70:30 in molar ratio. A copolymer is mentioned.

(F) (d) one or more unsaturated carboxylic acids selected from acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid and itaconic acid, and (e) styrene sulfone. Acid, 2-acrylamido-2-methylpropanesulfonic acid, 3-acryloxy-2
-One or more unsaturated sulfonic acids selected from hydroxy-propane sulfonic acid, vinyl sulfonic acid, allyl sulfonic acid and methallyl sulfonic acid, and (b) alkyl group having 1 to 8 carbon atoms Acid alkyl ester, methacrylic acid alkyl ester whose alkyl group has 1 to 8 carbon atoms, acrylic acid hydroxyalkyl ester whose alkyl group has 1 to 8 carbon atoms, and 1 to 8 carbon atoms
A copolymer or salt thereof formed from one or more monomers selected from methacrylic acid hydroxyalkyl esters, acrylamide, styrene, vinyl acetate and isobutylene of 8 and having a weight average molecular weight of 1,000 or less.
A preferable example of a copolymer of acrylic acid, 2-acrylamido-2-methylpropanesulfonic acid and acrylamide, or a salt thereof,
Its weight average molecular weight is 1,000 to 200,000, and the polymerization ratio of acrylic acid or its salt to 2-acrylamido-2-methylpropanesulfonic acid or its salt to acrylamide is 30:20:50 to 98: 1: 1 in a molar ratio. Among them, the weight average molecular weight is 5,000 to 100,
000, the polymerization ratio of acrylic acid or a salt thereof, 2-acrylamido-2-methylpropanesulfonic acid or a salt thereof, and acrylamide is 70:10:20 to 98: 1 in a molar ratio.
A copolymer of acrylic acid in the range of 1 with 2-acrylamido-2-methylpropanesulfonic acid and acrylamide or a salt thereof is preferable.

As a preferred specific example, the weight average molecular weight is 15,000, sodium acrylate and 2-acrylamido-2
-Sodium methyl propane sulfonate and acrylamide, a polymerization ratio of which is 70:10:20 in molar ratio, sodium acrylate and 2-acrylamide-2-copolymer of 2-methyl propane sulfonate sodium and acrylamide.

For the production of the above-mentioned polymer, a commonly used method can be used. For example, in the presence of a peroxide such as sodium persulfate or an azo compound such as azobisisobutyrol, in a non-aqueous solvent such as water, alcohol or toluene under a nitrogen gas stream, under normal pressure or under pressure. 50
After being polymerized at ˜150 ° C. for 1 to 10 hours and optionally neutralized with an alkali such as sodium hydroxide, a (co) polymer of each monomer can be obtained.

As the polymerization method, the whole amount of the monomer may be charged into the polymerization tank, or a method of dropping the whole amount or part of the monomer may be used. Alternatively, a monomer in the form of an alkali salt such as sodium salt may be polymerized in advance. The whole amount of the polymerization initiator may be charged into the polymerization tank, or a method of continuously charging may be used.

The most preferable example of the water reducing agent for the ultra-high pressure jet injection method of the present invention is sodium gluconate and sodium polyacrylate (weight average molecular weight 1
0,000), sodium polyacrylate (weight average molecular weight 100,0
00), sodium polyacrylate (weight average molecular weight 300,000
), Ammonium polyacrylate (weight average molecular weight 10,
000), a copolymer having a weight average molecular weight of 10,000 obtained by the reaction of 70 mol% sodium acrylate and 30 mol% methacrylic acid, obtained by the reaction of 90 mol% sodium acrylate and 10 mol% acrylamide Copolymer with a weight average molecular weight of 10,000, 95 mol% sodium acrylate and sodium maleate 5
A copolymer having a weight average molecular weight of 10,000 obtained by the reaction with mol%, and a weight average molecular weight obtained by the reaction of 70 mol% of sodium acrylate and 30 mol% of sodium styrenesulfonate are
Copolymer having a weight average molecular weight of 15,000 obtained by the reaction of 12,000 copolymer, sodium acrylate 70 mol% and sodium acrylamide propane sulfonate 30 mol%, sodium acrylate 70 mol% and sodium acrylamide propane sulfonate Examples thereof include those containing a copolymer having a weight average molecular weight of 15,000 obtained by the reaction of 10 mol% and 20 mol% of acrylamide.

The water-reducing agent of the present invention is a cement, and other additives added as necessary, such as calcium chloride, based on a conventional method when the super-high pressure jet injection method is applied.
A hardening accelerator such as triethanolamine or calcium thiocyanate, etc., and further water or the like, or separately, is sent to an injection rod that is pulled up while rotating, and is injected into the soil at high pressure from an injection nozzle. As a result, required solids are formed in the soil, while slime is discharged to the ground surface. However, the water reducing agent of the present invention has lower COD and BOD than conventional water reducing agents. The slime can be easily processed due to its high temperature. That is, the discharged slime is processed on-site or carried out to another treatment plant. At that time, although the water separated from the slime contains a water reducing agent, COD and B
Since its OD is low, it can be released as it is to rivers and the sea.

The amount of the water reducing agent used in the present invention varies depending on the type of soil, the amount of water, the amount of cement, etc.
Generally, (A) oxycarboxylic acid or its salt is contained in an amount of 0.0001 to 55%, preferably 0.01 to 20%, relative to the weight of the cementite-added clay having an initial water content of 1.0 to 3.0 WL%.
The polymers or salts of (B) to (F) are 0.0001 to 55%,
Preferably, it is about 0.1 to 20%. Here, WL is the liquid limit of cohesive soil.

[0030]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in more detail below with reference to test examples.

Test Example Using a Hobart type mortar mixer, first, 760 kg of ordinary Portland cement, 12 kg (10 l) of a water reducing agent, and water
Knead 750 l and low speed for 3 minutes to obtain cement milk,
Next, add the sample soil shown in Table 1 to this cement milk (mixing ratio of cement milk and sample soil is 8: 2 by volume).
Then, after kneading at low speed for another 5 minutes to prepare test evaluation soil, it was immediately put into a metal cylindrical mold (summit can) having an inner diameter of 10 cm and a depth of 20 cm, and the concrete floor mold was lightly hit to compact it. After 1-2 hours, pipette the bleeding water exuding on the top surface of the test soil.
50 ml was sampled and put in a glass sample bottle to prepare a COD test sample. The upper surface of the mold was covered with a glass plate to prevent drying until the bleeding water was collected.

The COD measurement results of the obtained COD test sample were used as the water reducing agent and its COD.
(Measured value based on JIS K 0102-21 and 32) and further shown in Table 2 together with the viscosity.

[0033]

[Table 1]

[Table 2] Next, a mixture of cement, a water reducing agent and water in the same proportion as above was applied as a hardening agent liquid to an actual ultra-high pressure jet injection method, and its effect was investigated.

That is, a hardening material liquid and compressed air are supplied to a predetermined pouring rod inserted in the ground, and a high-pressure hardening material liquid is jetted together with the compressed air from an injection nozzle provided at a monitor at the tip of the pouring rod. It was pulled up while rotating, and a columnar solidified body was formed in the ground. Water was separated from the slime discharged to the surface as the injection rod was pulled up, and its COD and BOD were measured. Sodium polyacrylate and sodium gluconate were used as water-reducing agents either individually or in combination. It was confirmed that all of them were below the environmental standard.

[0035]

As described above, according to the water reducing agent for the super-high pressure jet injection method of the present invention, CO of water contained in the sludge is
Since it is possible to reduce D and BOD, it is possible to easily treat the sludge that accompanies the construction of the ultra-high pressure jet injection method.

[0036]

Claims (4)

[Claims] 1. A monomer produced from one or more monomers selected from (A) an oxycarboxylic acid or a salt thereof, and (B) an acrylic acid, a metacrylic acid, a vinyl acetic acid and a crotonic acid. A homopolymer, a copolymer, or a salt thereof having a weight average molecular weight of 1,000 to 500,000, (C) (a) acrylic acid and / or methacrylic acid, and (b) the number of carbon atoms of the alkyl group 1-8 acrylic acid alkyl ester, alkyl group having 1-8 carbon atoms of methacrylic acid, alkyl group having 1-8 carbon atoms
Acrylic acid hydroxyalkyl ester, methacrylic acid hydroxyalkyl ester having 1 to 8 carbon atoms in the alkyl group, a copolymer formed from one or more monomers selected from acrylamide, styrene, isobutylene and vinyl acetate. Polymers or salts thereof having a weight average molecular weight of 1,000 to 500,000, (D) (a) acrylic acid and / or methacrylic acid, and (c) maleic acid, maleic anhydride, fumaric acid and itaconic acid A copolymer produced from a monomer of one or more unsaturated dicarboxylic acids selected from the above, or a salt thereof, having a weight average molecular weight of 1,000 to 500,000, (E) (D) Acrylic acid, methacrylic acid, maleic acid,
One or more unsaturated carboxylic acids selected from maleic anhydride, fumaric acid and itaconic acid, and (e)
Styrene sulfonic acid, 2-acrylamido-2-methylpropane sulfonic acid, 3-acryloxy-2-hydroxy-
A copolymer or a salt thereof produced from one or more unsaturated sulfonic acids selected from propanesulfonic acid, vinylsulfonic acid, allylsulfonic acid and methallylsulfonic acid, and having a weight average molecular weight of 1,000. ~ 300,
And (F) (d) acrylic acid, methacrylic acid, maleic acid,
One or more unsaturated carboxylic acids selected from maleic anhydride, fumaric acid and itaconic acid, and (e)
One selected from styrene sulfonic acid, 2-acrylamido-2-methyl propane sulfonic acid, 3-acryloxy-2-hydroxy-propane sulfonic acid, vinyl sulfonic acid, allyl sulfonic acid and methallyl sulfonic acid or
Two or more types of unsaturated sulfonic acid, and (b) alkyl group alkyl ester having 1 to 8 carbon atoms, methacrylic acid alkyl ester having 1 to 8 carbon atoms in the alkyl group, and alkyl group having 1 to 8 carbon atoms in the alkyl group. ~ 8 acrylic acid hydroxyalkyl ester, methacrylic acid hydroxyalkyl ester having 1 to 8 carbon atoms, co-polymer produced from one or more monomers selected from acrylamide, styrene, vinyl acetate and isobutylene A water reducing agent for an ultra-high pressure jet injection method, characterized in that it contains at least one selected from a compound or a salt thereof having a weight average molecular weight of 1,000 to 500,000. 2. An oxycarboxylic acid or a salt thereof of (A) and at least one selected from polymers of (B) to (F) or a salt thereof.
The water reducing agent for the ultra high pressure jet injection method described. 3. The water reducing agent for an ultrahigh pressure jet injection method according to claim 1, which contains (A) an oxycarboxylic acid or a salt thereof and a polymer (B) or a salt thereof. 4. The oxycarboxylic acid or its salt of (A) is sodium gluconate, and the polymer or its salt of (B) is polyacrylic acid sodium having a weight average molecular weight of about 10,000. 4. Any one of claims 1 to 3
The water reducing agent for the ultra-high pressure jet injection method described in item 1.