JPH06322367A - Soil property hardener - Google Patents

Abstract

PURPOSE:To obtain a soil property hardener, capable of rapidly hardening hydrous soil and preventing the ground from weakening and useful for civil engineering works, etc., by blending a highly water absorbing resin with a compound such as a sulfite. CONSTITUTION:The objective soil property hardener is obtained by blending (A) a highly water absorbing resin such as a cross-linked acrylic salt polymer with (B) one or more compounds selected from sulfites such as sodium sulfite, L-ascorbic acid and ferrous salts such as FeSO4. Furthermore, the blending weight ratio of the components (A) to (B) is preferably (2000/1) to (1/10).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a soil-solidifying agent for effectively solidifying hydrated soil such as highly hydrated cohesive soil, sandy soil, sludge, highly organic soil, sludge and silt.

[0002]

2. Description of the Related Art Conventionally, the earth and sand generated during civil engineering work are very difficult to handle because they contain a large amount of water and are highly fluid, and particularly make it difficult to carry them out by a belt conveyor or a dump truck. There is. For this reason, a technique has been developed in which a super absorbent resin is added to hydrous soil to solidify the soil. However, in such a method, when the soil containing the obtained superabsorbent resin is used for landfilling or leveling, etc., the water in the resin is also evaporated during drying to stabilize the ground, but due to rainfall, etc. When a large amount of water is applied, the resin absorbs water and swells, so that the ground becomes weak. Therefore, as a solution to such a drawback, a treatment method in which a polyvalent metal compound is added to the soil containing the superabsorbent resin to lose the water absorbing ability of the superabsorbent resin (JP-A-63-15037).
4) has been developed.

[0003]

However, such a method involves adding a superabsorbent resin to a water-containing soil to solidify the soil once, and then adding a polyvalent metal compound, which requires time and effort for the treatment step. The cost is high, which is very disadvantageous industrially.

[0004]

[Means for Solving the Problems] Therefore, the present inventors have obtained a soil solidifying agent which can rapidly solidify a water-containing soil, and which does not collapse even when the solidified soil is exposed to wind and rain, and does not weaken the ground. As a result of intensive studies, a soil-solidifying agent obtained by blending a super absorbent polymer with at least one compound selected from sulfite, L-ascorbic acid and ferrous salt meets such purpose. They have found the present invention and completed the present invention. That is, the soil-solidifying agent of the present invention is prepared by blending at least one compound selected from sulfite, L-ascorbic acid and ferrous salt with a superabsorbent resin to give the soil-solidifying agent to a water-containing soil. Solidification occurs rapidly by the action of the superabsorbent resin when added, and the compound loses the water-absorbing ability of the superabsorbent resin after solidification of the water-containing soil, and prevents re-swelling of the solidified soil. As described above, it is not necessary to treat the water-containing soil once and then to add the polyvalent metal compound to the solidified soil, which greatly improves the working and economic aspects. Hereinafter, the present invention will be described in detail.

The highly water-absorbent resin in the present invention refers to a resin which absorbs water and swells its volume by several to 1,000 times without being dissolved in water. For example, cross-linked acrylic acid polymer and acrylic acid. Ester-saponified product of vinyl acetate copolymer, starch-acrylic acid salt graft copolymer cross-linked product, saponified product of starch-acrylonitrile graft copolymer cross-linked product, maleic anhydride grafted polyvinyl alcohol cross-linked product, polyethylene oxide cross-linked product, Copolymer cross-linked product consisting of maleic anhydride and olefins, maleic anhydride-vinyl acetate copolymer saponified cross-linked product, polysaccharide-acrylic acid graft cross-linked product, carboxymethyl cellulose cross-linked product, acrylamide polymer cross-linked product, etc. Can be mentioned. Above all, due to its fast solidification rate, it has a high water-absorbing property containing an acrylate such as a cross-linked acrylic acid polymer, a saponified acrylic ester-vinyl acetate copolymer, and a cross-linked starch-acrylic acid graft copolymer. Resins are preferred.

The polymer granules usually have an average particle size of 50-
It is preferably about 850 μm, and if the particle size is too large, it is difficult to uniformly mix it with the soil and the solidification time is long, which is not preferable. Examples of the sulfite used in the present invention include sodium sulfite, potassium sulfite, sodium bisulfite, and the like, and formaldehyde sodium sulfoxylate dihydrate called Rongalit (trade name) can also be used. Further, as the first iron salt, FeSO ₄ , FeCO ₃ , Fe (NO ₃ ) ₂ ,
Fe (ClO _{4) 2} and the like.

In the present invention, the greatest feature is that the above-mentioned sulfite, ferrous salt and at least one compound selected from L-ascorbic acid are blended in the superabsorbent resin. The compound may be one kind, or a combination of two kinds or three kinds. The blending weight ratio of the super absorbent polymer and the compound in the present invention is preferably super absorbent resin / compound = 2000/1 to 1/10, more preferably 1000/1 to 1/2 and particularly 300 /. 1 to 1/1 is preferable. If the blending weight ratio is smaller than the above range, the solidification rate of the hydrous soil cannot be maintained, and conversely, if it is larger than the range, the effect of suppressing re-swelling of the solidified soil tends to be insufficient.

The amount of the soil solidifying agent of the present invention to be added to soil varies depending on the properties of the soil to be solidified and cannot be unconditionally limited. Parts, preferably 0.1 to 5 parts by weight. When using the soil solidifying agent of the present invention, if necessary, inorganic powder such as silicon dioxide, wet silica, dry silica, zeolite, bentonite, diatomaceous earth, talc, perlite, silica sand, activated clay and the like optional components Can be used together. As the water-containing soil using the soil solidifying agent of the present invention, it is possible to use any of high-moisture specific viscosity soil, sandy soil, sludge, high organic soil, sludge, silt, and any other soil requiring solidification treatment. The addition method of the soil solidifying agent in the present invention is not limited at all, for example, a method of premixing the superabsorbent resin and the compound and adding to the soil, a method of separately adding each component to the soil and the like. To be Further, the soil solidifying agent of the present invention can be added all at once or divided into several times.

[0009]

[Operation] The soil solidifying agent of the present invention, which contains a specific compound in the super absorbent polymer, rapidly solidifies the water-containing soil and softens the soil even when the soil is exposed to rainfall or the like. It can be prevented.

[0010]

EXAMPLES The present invention will be specifically described below with reference to examples. In the examples, "%" means weight basis unless otherwise specified. Example 1 Aqua Reserve AP-100 (Nippon Synthetic Chemical Industry Co., Ltd.)
Manufactured by the company, polyacrylic acid superabsorbent resin) / sodium sulfite = 30/1 (weight ratio) mixed with soil-solidifying agent on soft soil (ratio of water to soil in water-containing soil 50% cohesive soil) 5 kg / m ³ (water-containing state) was added to and mixed with (1) and the solidified soil was filled on a 48-mesh sieve, and the corn index after 1 and 24 hours was measured. Further, after the solidified soil was left in a standard state for 4 days, water was sufficiently sprayed (rainfall was assumed), and the corn index after 24 hours and 4 and 9 days was measured. As the conditions for measuring the cone index, an average value was adopted when the mold size was 150 mm in inner diameter and 175 mm in height, and the penetration depth of the cone was 5 cm and 10 cm.

Example 2 In Example 1, the soil solidifying agent was changed to Aqua Reserve AP-
100 (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., polyacrylic acid salt-based super absorbent polymer) / L-ascorbic acid = 50/1
The cone index was measured in the same manner as in Example 1 except that the mixture was used in the ratio (weight ratio). Example 3 In Example 1, the soil solidifying agent was changed to Aqua Reserve AP-
Same as Example 1 except that the mixture was 100 (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., polyacrylic acid salt-based super absorbent polymer) / ferrous sulfate = 100/1 (weight ratio). The cone index was measured.

Example 4 In Example 1, the soil solidifying agent was changed to Aqua Reserve AP-
100 (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., polyacrylic acid salt-based super absorbent polymer) / potassium sulfite / ferrous sulfate = 1 = 3
The cone index was measured in the same manner as in Example 1 except that the mixture was 0/1 / 0.5 (weight ratio). Comparative Example 1 As a soil-solidifying agent, Aqua Reserve AP-100 (manufactured by Japan Synthetic Chemical Industry Co., Ltd., polyacrylic acid superabsorbent resin) was used alone to carry out an experiment in accordance with Example 1 to obtain a cone index. Was measured. Table 1 collectively shows the measurement results of the Cone index of Examples and Comparative Examples.

[0013]

[Table 1] Cones 1 hour after 24 hours after 1 day after spraying 4 days after spraying 9 days after spraying Example 1 1.5 1.5 1.5 1.5 1.8 2.0 Example 2 1.5 1. 6 1.7 1.8 2.0 Example 3 1.5 1.7 1.8 2.0 2.0 2.2 Example 4 1.5 1.7 1.9 2.1 2.4 Comparative Example 1 1 .5 1.3 0.5 0.5 0.5 0.6 Note) 1 day after spraying means 6 after mixing the soil solidifying agent and the soft soil.
Indicates the day after.

[0014]

[Effects] The soil-solidifying agent in the present invention is such that by adding a specific compound to the superabsorbent resin, solidification occurs rapidly when the soil-solidifying agent is added to the water-containing soil, and what kind of treatment is applied to the solidified soil. Even without doing so, it is possible to prevent softening of the solidified soil due to rainfall, etc., which is very advantageous in terms of work and economy.

Claims (2)

[Claims] 1. A soil solidifying agent comprising a highly water-absorbent resin and at least one compound selected from sulfite, L-ascorbic acid and ferrous salt. 2. The blending weight ratio of super absorbent polymer / compound is 2
It is 000/1 to 1/10 and Claim 1 characterized by the above-mentioned.
Soil solidification agent described.