JP2001129507A - Additive composition for underground water barrier wall and construction method for continuously integrated underground water barrier wall solid body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To add a required high water barrier property to a continuously integrated underground water barrier wall for preventing pollutants from percolating by uniformly distributing bentonite in the continuously integrated underground water barrier wall, remarkably enhancing a water barrier effect with the aid of swelling and thickening by the bentonite itself, and allowing those swelling and water barrier function to be thoroughly demonstrated. SOLUTION: In an additive composition for underground water barrier wall having powdery bentonite and powdery dispersant or liquid-like dispersant as main components, the dispersant is at least one kind of a compound selected from (a) citric acid gluconic acid, pyrophosphoric acid, polyphosphoric acid, fumic acid and salts thereof and (b) monopolymer comprising acrylic acid and its salt, a copolymer comprising maleic acid and isoamylene and its salt. The additive composition for underground water barrier used for preparing an underground water barrier wall solid body having a water permeation constant of at most 5×10-7 cm/s, and a construction method for the continuously integrated underground water barrier wall solid body are provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an additive composition for an underground impermeable wall and a method for constructing a continuous integrated underground impermeable wall. More specifically, the present invention relates to general waste, industrial waste and the like. The final disposal site is a managed waste final disposal site, a garbage incineration plant,
Additive composition for underground seepage control walls used to create solidified underground seepage control walls to reliably block and contain leaching of contaminants and contaminated water from contaminated soil and sources such as factory land And a method of constructing a continuous integrated underground impermeable wall using the composition.

[0002]

2. Description of the Related Art
In order to perform ground improvement, temporary walls, mountain retaining, and the like, a soil-cement-solidified construction method of solidifying the ground with cement has been performed. As a method of kneading and constructing this soil cement, there is also a mode using a casing pipe, but using an auger in which a spiral fin is fixed to a shank, excavating soil under the ground, preparing a soil cement slurry, and preparing the soil cement. 2. Description of the Related Art Construction for forming an underground structure of a soil cement solidified body by curing and hardening a cement slurry is widely performed.

[0003] However, in the above-described method for constructing a soil cement solid body, cement and water are added to the excavated soil and mixed to form a soil cement slurry in a fluidized state, and then the soil cement slurry is cured and cured. In the process of forming a wall, it is difficult for these materials to be in a uniform mixed and dispersed state, and therefore, there has been a problem that the water barrier of the soil cement consolidated body is reduced.

[0004] In particular, in recent years, the final disposal site for general waste, industrial waste, etc., is a managed waste final disposal site, a garbage incineration plant,
There is a need to reliably block and contain leaching of pollutants and contaminated water from contaminated soil and pollution sources such as factory lands, etc. However, conventional soil-cement walls have inadequate water-blocking properties, and have not been able to respond sufficiently.

In order to solve these problems, Japanese Patent Application Laid-Open No. Sho 62-3392 has been proposed for the purpose of improving the water shielding of a soil cement wall.
A method of first swelling bentonite described in JP-A No. 3 and a method of mixing a water-soluble organic solvent with bentonite described in JP-A-3-233016 have been proposed.

[0006] In addition, a method of increasing the fluidity by adding additives such as water, cement and a dispersant to excavated soil has been performed. For example, JP-A-5-79033 proposes to use dispersants such as humates, polyphosphates, and ligninsulfonates. Also, JP-A-7-25
JP-A-7951, JP-A-10-95976, and JP-A-11-254425 propose to use a polyacrylate as a dispersant.

[0007] However, by simply improving the above bentonite and adding a dispersing agent, continuous construction is carried out for the purpose of preventing leaching of contaminants and contaminated water from a controlled waste final disposal site, a garbage incineration plant, and a factory site. In order to obtain a continuously integrated underground impermeable wall having a water permeability required for the integrated underground impermeable wall of the order of 10 ^-7 cm / sec or less, preferably of the order of 10 ^{-8 to} 10 ^-9 cm / sec. Has not been reached,
Further improvement and development were desired.

The present invention has been made in view of the above circumstances, and reliably prevents leaching of contaminants and contaminated water from contaminated soil and sources such as a managed waste landfill, a garbage incineration plant, and a factory site. Additive composition for an underground impermeable wall used to construct a continuously integrated underground impermeable wall structure (consolidated body) having high water impermeability, and continuous integrated underground impermeable wall using the composition It is intended to provide a method for building a body.

[0009]

Means for Solving the Problems and Embodiments of the Invention As a result of intensive studies to achieve the above object, the present inventor has found that powdered bentonite and powdered or liquid dispersant are the main components. It has been found that the additive composition for underground impermeable walls is suitable for construction of a continuously integrated underground impermeable wall structure (consolidated body).

That is, powdered bentonite, (a) a homopolymer of citric acid, gluconic acid, pyrophosphoric acid, polyphosphoric acid, humic acid and salts thereof and (b) acrylic acid and salts thereof, acrylic acid and maleic acid An underground water barrier mainly comprising a copolymer of an acid and a salt thereof, a copolymer of maleic acid and isoamylene and an effective component of at least one powdery or liquid dispersant selected from a salt thereof. When the wall additive composition is added to the cement slurry, the powdery bentonite can be uniformly dispersed, the water barrier effect due to the swelling and thickening action of the bentonite itself is fully exhibited, and the water permeability is 5 × 10 5 it is possible to construct a continuous integrated underground water shield wall caking having a ^-7 cm / sec or less of the high water-blocking, with high strength and good flowability, managed waste Things landfills, incinerators, found that it is optimal for the construction of continuous integral underground water shielding wall structure, such as industrial sites (Katayuitai), the present invention has been accomplished.

Further, according to the construction method of the present invention, the cement slurry containing the composition of the present invention, cement and water is mixed with underground soil excavated by a kneading excavator,
A vertical wall that reaches the tip of the underground water-impermeable layer is continuously and integrally constructed, cured and hardened to create a controlled waste final disposal site, garbage incineration plant, factory site, etc. A continuously integrated underground impermeable wall having a water permeability of 5 × 10 ⁻⁷ cm / sec or less can be created, and the viscosity decreases, so that the pumpability of the cement slurry is remarkably improved, and high water impermeability is achieved. And a continuous integrated underground impermeable wall with good strength can be created with high construction efficiency.

Accordingly, the present invention firstly provides an additive composition for underground impermeable walls comprising powdery bentonite and a powdery dispersant as main components, wherein the powdery dispersant comprises (a) Citric acid, gluconic acid, pyrophosphoric acid, polyphosphoric acid, humic acid and salts thereof, (b) a homopolymer of acrylic acid and salts thereof, a copolymer of acrylic acid and maleic acid and salts thereof, and maleic acid It is at least one compound selected from a copolymer of isoamylene and a salt thereof, and is used for forming an underground impermeable wall solid body having a water permeability of 5 × 10 ⁻⁷ cm / sec or less. Secondly, an underground impermeable wall additive composition comprising powdered bentonite and a liquid dispersant as main components, wherein the liquid dispersant is effective. Minutes
(A) citric acid, gluconic acid, pyrophosphoric acid, polyphosphoric acid, humic acid and salts thereof, and (b) a homopolymer and a salt thereof of acrylic acid, a copolymer of acrylic acid and maleic acid and a salt thereof, It is at least one compound selected from a copolymer of maleic acid and isoamylene and a salt thereof, and has a water permeability of 5 × 10 ⁻⁷ cm / sec.
c. an additive composition for an underground impermeable wall, which is used for forming an underground impermeable wall consolidated body of c or less;
Then, by mixing a cement slurry containing the above composition, cement and water with the underground soil excavated by a kneading excavator, a vertical wall reaching a tip to an impermeable layer underground is continuously and integrally constructed. This is cured and cured, and a continuous integrated underground shield with a coefficient of permeability of 5 × 10 ⁻⁷ cm / sec or less is created around the target land for construction, such as a final disposal site for managed waste, a garbage incineration plant, or a factory site. Provided is a method for constructing a continuous integrated underground impermeable wall solidified by forming a water wall.

Hereinafter, the present invention will be described in more detail. The additive composition for underground impermeable walls of the present invention contains powdery bentonite and at least one kind of powdery dispersant or liquid dispersant as main components.

Here, the bentonite powder of the present invention comprises:
Normal bentonite (alkali bentonite, alkali metal bentonite, etc.) can be used regardless of the place of production.

The bentonite is used in the form of a powder, and its water content is preferably 10% by weight or less.
0 mesh sieve residue is preferably 0.001 to 50% by weight, more preferably 200 mesh sieve residue is 0.01%.
３０30% by weight. In this case, particularly, the average particle diameter at the time of wet measurement in which bentonite is dispersed in water is 0.01 to 5 μm.
Those having a range of m are preferred.

As an effective component of the powdery dispersant or the liquid dispersant of the present invention, at least one compound selected from the following components (a) and (b) is used.

(A) Citric acid, gluconic acid, pyrophosphoric acid, polyphosphoric acid, humic acid and salts thereof, particularly citric acid, gluconic acid and salts thereof are preferred. When these are made liquid, they are dissolved in water or a mixture of water and alcohol. (B) A homopolymer of acrylic acid and its salt, a copolymer of acrylic acid and maleic acid and its salt, and a copolymer of maleic acid and isoamylene and its salt.

Specific examples of the dispersant of the component (b) include (i) a homopolymer of acrylic acid or a salt thereof having a weight average molecular weight in the range of 1,000 to 200,000. (Ii) a copolymer of acrylic acid and maleic acid or a salt thereof, having a weight average molecular weight of 1,000 to
In the range of 200,000, the polymerization ratio of acrylic acid or a salt thereof is 50 to 99 mol%, and that of maleic acid or a salt thereof is 1%.
(Iii) a copolymer of maleic acid and isoamylene or a salt thereof, wherein the weight average molecular weight is in the range of 1,000 to 200,000 and the polymerization ratio is maleic acid or a salt thereof. A compound in which 10-90 mol% and isoamylene are in the range of 10-90 mol%, (iv)
A copolymer of acrylic acid and maleic acid or a salt thereof, having a weight average molecular weight in the range of 5,000 to 100,000, and a polymerization ratio of 80 to 99 mol% of acrylic acid or a salt thereof, maleic acid or a salt thereof. A compound having a salt content of 1 to 20 mol%, (v) a copolymer of maleic acid and isoamylene or a salt thereof, having a weight average molecular weight of 5,000 to 100,
In the range of 000, compounds having a polymerization ratio of maleic acid or a salt thereof in the range of 20 to 80 mol%, isoamylene in the range of 20 to 80 mol%, and the like can be used alone or in combination of two or more. They can be used in combination.

Examples of the salt of the (co) polymer of the component (b) include water-soluble salts such as ammonium salts, alkali metal salts (sodium salts, potassium salts), and alkaline earth metal salts (calcium salts, magnesium salts). Salts may be mentioned, but they may be substituted with amine salts such as monoethanolamine, diethanolamine, ethylamine, ethylenediamine, diethylenetriamine and the like. Further, an unneutralized portion may remain. Among them, sodium salts and alkaline earth metal salts are preferred. In particular, in the case of a powder, an alkaline earth metal salt is preferable because it has low hygroscopicity and does not generate lumps.

Among these, the above-mentioned (i), (ii) and (iv), which are a homopolymer of acrylic acid or a copolymer of acrylic acid and maleic acid, are used in the form of powder when used in the form of alkali. Preferably, it is an earth metal salt. The copolymers of maleic acid and isoamylene or their salts (iii) and (v) are alkaline earth metal salts which have high hygroscopicity and do not produce lumps even if they are alkali metal salts, so that the production cost is high. A powder having good characteristics can be provided without using a metal salt.

In the present invention, by using the above components (a) and (b) in combination, the fluidity of the soil cement slurry can be maintained for a long time, and the flexibility of operation can be increased. This is preferable because the soil cement slurry can maintain good fluidity without thickening and gelling even if the water used at the construction site has a high hardness.

When the component (a) and the component (b) are used in combination, at least one selected from citric acid, gluconic acid and salts thereof as the component (a) among the above components (a) and (b). It is preferable to use a combination of at least one selected from a copolymer of maleic acid and isoamylene and a salt thereof, a homopolymer of acrylic acid or an alkaline earth salt of a copolymer as the component (b). Component (a) and component (b) may be used in combination at a weight ratio of component (a) / component (b).
(B) component = 1/99 to 99/1, preferably 10/9
0 to 90/10. When the component (a) and the component (b) are used in combination, it is preferable that both the components (a) and (b) are in a powder form.

The polymer dispersant of the component (b) can be produced by a commonly used method. For example, in the presence of a persulfate such as ammonium persulfate, potassium persulfate, or sodium persulfate, or an azo compound such as azobisisobutyronitrile, a stream of nitrogen gas in a non-aqueous solvent such as water, alcohol, or toluene. After polymerization at 50 to 150 ° C for 1 to 10 hours under normal pressure or pressure, the (co) polymerized solution of each monomer is neutralized with an alkali, for example, sodium hydroxide, if necessary. Obtainable. When the component (b) is used in a liquid state, the (co) polymerization liquid of each monomer can be used as it is or preferably diluted with water.

On the other hand, when the component (b) is used as a powder, the (co) polymerized solution of each monomer is pulverized by a conventional method such as a kneading drying method or a spray drying method. When the components (a) and (b) are used as a powdery dispersant, it is usually preferable to use one having an average particle size of about 1 to 200 μm.

In the present invention, the ratio of the powdered bentonite to the dispersant can be set arbitrarily. The effective amount of the dispersant is 0.1 to 99.9% by weight based on the powdered bentonite.
1 to 99.9% by weight, more preferably 50 to 99% by weight of powdered bentonite, the effective amount of the dispersant is 1 to 50%.
It is preferable to mix by weight%. Here, the effective amount of the dispersant means a solid content of the dispersant.

In this case, the amount of powdered bentonite used for the target soil is 0.1 to 80 with respect to 1.0 m ³ of the target soil.
kg, preferably in the range of 1 to 40 kg. In addition, the amount of cement, to the target soil 1.0m ³ 10
It is added in the range of 0 to 500 kg, preferably 200 to 400 kg. The water / cement ratio (W / C) of the cement slurry is 50 to 350% by weight, preferably 100 to 350% by weight.
300% by weight. In this case, it is preferable to use excavated soil generated on site in the excavation and kneading process. As the cement, ordinary cements such as Portland cement, early-strength cement, blast furnace cement, and fly ash cement can be used.

When a powdery dispersant is used, the additive composition for underground impermeable walls according to the present invention is prepared by mixing the powdery dispersant in advance with powdered bentonite and then mixing with cement and water. As a slurry (cement milk), this cement slurry can be added to soil and uniformly mixed. Further, the powdery bentonite and the powdery dispersant may be separately mixed with cement and water to form a cement slurry (cement milk), and this cement slurry may be added to soil and uniformly mixed.

When a liquid dispersant is used, the additive composition for underground impermeable walls according to the present invention is prepared by separately mixing powdered bentonite and the liquid dispersant with cement and water, and cement slurry (water). As cement milk), it is preferable to add this cement slurry to soil and uniformly mix it.

It is necessary that the cement slurry thus obtained is cured and hardened, and the hydraulic conductivity of the underground impermeable wall solidified body of the present invention is 5 × 10 ⁻⁷ cm / sec or less.
Preferably 5 × 10 ⁻⁷ cm / sec to 5 × 10 ⁻¹¹ cm
/ Sec.

According to the law, the hydraulic conductivity of the underground impermeable wall solidified body at the final disposal site for industrial waste is 1 × 10 ^-6 c
m / sec or less, 5 × 10 5
This is because it is necessary to be ^-7 cm / sec or less. On the other hand, it is not necessary to set the water blocking coefficient to less than 5 × 10 ⁻¹¹ cm / sec, and on the contrary, the cost may be increased and the economic efficiency may be reduced.

Here, the hydraulic conductivity in the present invention is shown in FIG.
Is set in the hydraulic conductivity measuring device 1 with the surroundings of the test sample 2 having a predetermined size surrounded by the sealing material 3 and the lower surface side of the test sample 2 by the porous stone 4. The amount and time of water flowing out from the water tank 6 connected to 5 to the specimen 2 under a constant pressure are measured, and it can be obtained from the relationship between the applied pressure, the amount of flowing out and the time of flowing out.

Next, in the method for constructing a continuous integrated underground impermeable wall compact of the present invention, a cement slurry containing the underground impermeable wall additive composition, cement and water is mixed by a kneading excavator. By mixing with excavated underground soil, a vertical wall that reaches the tip of the underground water-impermeable layer is continuously and integrally constructed, cured and hardened, and finally managed waste disposal site and garbage incineration site In addition, a continuously integrated underground impermeable wall having a water permeability of 5 × 10 ⁻⁷ cm / sec or less is created around a construction destination such as a factory site.

FIG. 2 is a perspective view showing an example of a managed waste final disposal site in which a continuous integrated vertical impermeable wall is provided around the periphery. In this final disposal site, the vertical impermeable wall 7 is continuously and integrally formed so as to surround the perimeter, so that the contaminants, contaminated water, etc. leaked from the waterproof sheet 8 are prevented by the impermeable wall 7. Since the water is reliably blocked and no leakage occurs, and since the tip of the impermeable wall 7 reaches the impermeable layer underground, no leakage of contaminants, contaminated water, etc. from the bottom surface occurs. Therefore, this final disposal site has its side and bottom surfaces surrounded by impermeable walls, and contaminants, contaminated water, and the like are securely contained and do not leak from anywhere.

A kneading excavator is used to construct such a continuously integrated underground impermeable wall solidified body. As the kneading excavator, a multi-shaft excavator is preferable.In addition to the multi-shaft kneading excavator, for example, an endless kneading excavation chain arranged between sprockets supported above and below a cutter post, a wire or For hanging a basket type excavator at the end of a Cary bar, for hanging multiple drilling cutters at the end of a wire or a Cary bar, and for kneading and excavating on multiple horizontal shafts supported at the end of a wire or a Cary bar And the like provided with a cutter can be used.

As an example, a plurality of interconnected pipes (3 in FIG. 3) having the functions of excavation and kneading shown in FIG.
Using a kneading excavator (for example, a multi-axis kneading auger machine) 10 provided with a cement slurry discharge port 11 at the tip of the kneading shafts 9a, 9b, 9c of the present invention, the soil is excavated and the present invention Is added through the discharge port 11 at the tip of the kneading shaft, mixed with the excavated soil and stirred to form a soil cement slurry, which is cured and hardened. In this case, the kneading machine 3
The two kneading shafts 9a and 9c located on both sides of the kneading shaft are provided with expanding / contracting wings 13 which can be expanded / contracted outwardly behind the spiral fins 12, so that the wings or the expanding / contracting wings are provided as needed during the excavation. By contracting the blades, the borehole diameter can be increased (see FIG. 3). Thereby, even at a large depth, a constant wall thickness can be maintained, and a continuous integrated vertical impermeable wall can be reliably formed. The tip of the kneading shaft of the kneading excavator means a portion approximately 4 m from the lowermost end of the kneading excavator.

Then, as shown in FIG. 4, a series of steps including excavation kneading, repetitive kneading, pulling kneading, and formation of a continuous wall is repeated, and in each step, the additive composition of the present invention is added simultaneously with excavation. The obtained cement slurry is injected from the outlet 11 at the tip of the kneading shaft of the kneading excavator. In this case, as shown in the continuous wall forming step of FIG. 4, first, the first element 14 and the second element 15 that are close to each other are formed, and then the first and second elements 14 and 14 are formed.
By connecting the 15 and forming the third element 16 therebetween, the vertical wall can be constructed (completely wrapped) while overlapping the ground to be constructed without gaps. As a result, the permeability is 5 × 10 ⁻⁷ cm / sec, which has no gap and does not cause leakage of pollutants and contaminated water.
It is possible to construct a continuously integrated underground impermeable wall of c or less. In addition, since the tip of the underground impermeable wall reaches the underground water-impervious layer, there is no leakage of contaminants and contaminated water from the underground base, and the contaminants and contaminated water are securely contained inside. Can be done.

Further, by using the additive composition of the present invention, the cement slurry (cement milk) has good fluidity, is excellent in pumping property, and has excellent fluidity as a soil cement slurry. The construction efficiency is greatly improved, and when it is made into a hardened consolidated body, good strength can be maintained, and from this point, the management type waste final land, which is the final disposal site for general waste, industrial waste, etc. It is ideal for the construction of a continuously integrated underground impermeable wall for disposal sites, garbage incineration plants, and factory sites.

[0038]

According to the present invention, bentonite can be uniformly dispersed in a continuously integrated underground impermeable wall,
The water barrier effect by the swelling and thickening of bentonite itself can be remarkably promoted, the desired high water barrier can be given to the continuous integrated underground water barrier, and the leaching of pollutants, contaminated water, etc. to the outside Can be reliably prevented.

When the cement slurry to which the additive composition for underground impermeable walls of the present invention is added is used in a kneading excavator, the cement slurry to which the additive composition of the present invention is added is preferably pumped. From the tip of the kneading shaft of the kneading excavator (in this case, it means a portion approximately 4 m from the lowermost end of the kneading excavator) and mixes with the excavated soil to mix. In this case, the pumpability of the cement slurry greatly affects the construction efficiency.However, if the additive composition of the present invention is used, the viscosity of the cement slurry is reduced, so that the pumpability is significantly improved. In addition, it is possible to efficiently create a continuous integrated underground impermeable wall of a managed waste final disposal site, a garbage incineration plant, and a factory site, which are final disposal sites for general waste and industrial waste. .

[0040]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples.

[Examples 1 to 14, Comparative Examples 1 and 2] When the dispersant is in the form of powder, the ratio of bentonite / dispersant effective component was determined by combining the bentonite shown in Table 1 with the dispersant shown in Table 2 in Table 4. Were obtained to obtain an additive composition. When the dispersant is in a liquid state, the bentonite shown in Table 1 and the dispersant shown in Table 2 are separately added to water in a combination shown in Table 4, and mixed so as to have a ratio of bentonite / effective amount of the dispersant. A composition was obtained. When the dispersant is a liquid and powdered compound,
Bentonite, a liquid dispersant, and a powdery dispersant were separately added to water, and mixed to obtain a ratio of bentonite / effective dispersant to obtain an additive composition.

Next, the additives used in Table 1 were mixed in a mixing ratio shown in Table 3 with the additive composition and water using a soil mixer. Next, cement was charged and homogenized to obtain a cement slurry. The soil was added to this cement slurry, and the mixture was stirred and mixed with a soil mixer.
The soil cement slurries of Comparative Examples 1 and 2 were obtained.

[0043]

[Table 1]

[0044]

[Table 2] * In Table 2, the average particle diameter indicates a powder dispersant, and the effective component indicates a liquid dispersant.

[0045]

[Table 3]

Next, the performance of the obtained cement slurry and soil cement slurry was evaluated by the following method. Table 4 shows the results.

Consistency (fluidity) test Soil cement slurry immediately after production was prepared according to the Japan Highway Public Corporation standard.
A consistency test using a cylinder of IS A313-1992 was performed. The fluidity was evaluated by the flow (spread) of the soil cement slurry. Water permeability test Water permeability was evaluated using the water permeability coefficient measuring device shown in FIG. A cylindrical container of φ50 × 150 mm was filled with the soil cement slurry, and after one day, the surface was flattened, covered with a polyethylene film, cured and cured for 28 days. Thereafter, the upper and lower 5 cm of the cured product were removed and molded, and the central 5 cm portion was used as a test specimen. Next, the obtained specimen was set in the permeability measuring apparatus of FIG. 1, and the amount and time of water flowing out from the water tank connected to the compressor under a constant pressure were measured. The hydraulic conductivity was calculated from the relationship between the pressure, the outflow amount, and the outflow time. In addition, three specimens were prepared for each soil cement slurry,
The average was shown. Funnel Viscosity Test A 500 cc cement slurry was sampled and placed in a funnel viscometer to measure the time (seconds) required to flow out 500 cc. Uniaxial compressive strength After forming the specimen in a 50 mm x 100 mm
Curing was performed until the day, and the compressive strength was measured according to JIS A1108.

[0048]

[Table 4]

From the results shown in Table 4, Comparative Example 1 uses a conventional naphthalene-based dispersant and bentonite, and Comparative Example 2 does not include a dispersant. The flow value is smaller, the permeability is larger, and the compressive strength is lower. On the other hand, in Examples 1 to 14, it is recognized that soil, cement, and water can be uniformly dispersed and mixed in the slurry by the addition of bentonite and the dispersant, and have high water shielding properties and improved compressive strength. . Further, in Examples 1 to 14, the viscosity of the cement slurry was lower than that of the comparative example, the pumpability was improved, and the working efficiency was high.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram of a hydraulic conductivity measuring device for obtaining a hydraulic conductivity.

FIG. 2 is a perspective view of a managed waste final disposal site in which a continuous integrated underground impermeable wall is formed around the land;

FIG. 3 is a partially enlarged view of the kneading excavator.

FIG. 4 is an explanatory view showing a method for constructing a continuous integrated underground impermeable wall of the present invention.

[Explanation of symbols]

 7 impermeable wall 8 waterproof sheet 10 kneading excavator

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C04B 24/06 C04B 24/06 A 24/24 24/24 B 24/26 24/26 EZH 28 / 02 28/02 E02D 5/20 102 E02D 5/20 102 // C04B 103: 40 C04B 103: 40 111: 27 111: 27 (72) Inventor Katsushi Matsui 1-3-7 Honjo, Sumida-ku, Tokyo Rio (72) Inventor Koji Inada 1-37 Honjo, Sumida-ku, Tokyo Lion Corporation (72) Inventor Nobuo Hamamoto 1-13-13 Awaza, Nishi-ku, Osaka-shi, Osaka Nariyuki Industry Co., Ltd. In-company (72) Inventor Katsuhiko Yamanari F-term (reference) 2D049 EA01 EA14 GA13 GA15 GA16 GA17 GB01 GC11 GE20 4D004 AA46 BB04 4 D077 AB20 AC05 BA01 BA07 DA02Y DC28Y DC67Y DD08Y DD09Y DD13Y DD17Y DD20Y DD53Y DE10Y DE32Y 4G012 MC11 PA04 PA06 PB13 PB16 PB17 PB31 PB32 PC03 PC13

Claims (3)

[Claims] 1. An underground impermeable wall additive composition comprising powdery bentonite and a powdery dispersant as main components, wherein the powdery dispersant comprises: (a) citric acid, gluconic acid, pyrophosphoric acid , Polyphosphoric acid, humic acid and salts thereof, and (b) a homopolymer and its salt composed of acrylic acid, a copolymer and its salt composed of acrylic acid and maleic acid, and a copolymer composed of maleic acid and isoamylene and its At least one compound selected from salts having a water permeability of 5
An additive composition for an underground impermeable wall, which is used to form an underground impermeable wall solidified body of ^10-7 cm / sec or less. 2. An underground impermeable wall additive composition comprising powdery bentonite and a liquid dispersant as main components, wherein the effective component of the liquid dispersant is (a) citric acid, gluconic acid , Pyrophosphoric acid, polyphosphoric acid, humic acid and salts thereof, and (b) a homopolymer and a salt thereof comprising acrylic acid, a copolymer and a salt thereof comprising acrylic acid and maleic acid, and a copolymer comprising maleic acid and isoamylene At least one compound selected from the group consisting of coalesced salts and salts thereof, wherein the compound is used for forming an underground impermeable wall solidified body having a water permeability of 5 × 10 ⁻⁷ cm / sec or less. Wall additive composition. 3. A cement slurry containing the composition according to claim 1 or 2 and cement and water is mixed with underground soil excavated by a kneading excavator, so that a tip of the cement slurry reaches an underground impermeable layer. The vertical wall that reaches is continuously and integrally constructed, cured and hardened, and the permeability coefficient is 5 × around the construction destination, such as a managed waste final disposal site, a garbage incineration plant, and a factory site.
A method of constructing a continuously integrated underground impermeable wall solidified body, wherein a continuously integrated underground impermeable wall of 10 ^-7 cm / sec or less is created.