JPS645130B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention protects the soil surface by spraying an aqueous solution containing a fiber material and a coagulant for a synthetic resin aqueous emulsion onto the land surface, and then immediately spraying a synthetic resin aqueous emulsion to coagulate and form a film on the ground surface. It's about how to do it. Ground surfaces, especially slopes, are subject to severe erosion due to rainfall and running water, and conventional methods include planting seeds and seedlings of plants, water-soluble materials such as sodium polyacrylate, polyvinyl alcohol, polyacrylamide, carboxymethyl cellulose, and sulfite pulp waste liquid. Spraying and fixing methods using polymers, asphalt emulsions, synthetic resin aqueous emulsions, etc. have been implemented. In addition, large-scale civil engineering works include mortar spraying and pouring of reinforced concrete protective walls. However, the use of vegetation greening methods is limited to areas suitable for vegetation because they tend to cause erosion of the ground surface and wash away seeds and seedlings until plants grow and protect the ground surface. The method of spreading and fixing water-soluble polymers on land has the disadvantage that the effect lasts only for a short time because the fixation layer has poor water resistance. The adhesive layer of asphalt emulsion is easily cracked, and its water resistance is not very high. Synthetic resin aqueous emulsions are inherently incapable of adhesion unless they are completely dry, so there may be cases where there is too much water on the ground surface where they are sprayed, or where it rains before it dries after spraying. As a result, the spray liquid becomes excessively diluted, and its original characteristics are often not utilized. In contrast, according to the method of the present invention, the aqueous synthetic resin emulsion does not dilute and run away, and a film is reliably and immediately coagulated on the soil surface, resulting in a very large effect. The method of the present invention begins by spraying onto the ground surface an aqueous solution containing a coagulant for an aqueous synthetic resin emulsion mixed with a fibrous material. The fibrous material is not particularly limited, but wood pulp is most preferred because of its dispersibility in an aqueous solution containing a coagulant, its water absorbency, and its ability to cover the ground surface after being spread. As coagulants for synthetic resin aqueous emulsions, water-soluble salts of divalent or trivalent metals are preferred, and specifically aluminum sulfate, aluminum chloride, polyaluminum chloride, calcium chloride, magnesium chloride, and magnesium sulfate are preferred. After the application of the aqueous solution containing the fiber material and coagulant, the aqueous synthetic resin emulsion is subsequently applied. Synthetic resin aqueous emulsions must have good water resistance and weather resistance after film formation, and include acrylic styrene, acrylic, vinyl acetate/ethylene, vinyl acetate/beoba, SBR, MBR,
Examples include vinyl chloride type and vinylidene chloride type, but any type may be used as long as it can be immediately coagulated by a coagulant, and these can be used alone or in combination of two or more types. A method is already known in which a coagulating agent is added to an aqueous synthetic resin emulsion to flocculate it and then sprayed on the ground surface (Japanese Patent Publication No. 47-39163 and Japanese Patent Publication No. 48-9325), but this method does not cause aggregation. It is often incomplete or the coagulum forms into clumps, making it very difficult to spread it evenly or to cover the entire ground surface uniformly. Furthermore, the film-forming properties are poor, and the only effect that can be obtained is that the solidified matter is scattered on the ground surface. In contrast, according to the method of the present invention, a homogeneous and complete film can be formed, and therefore a sufficient effect of strengthening the fixation of the ground surface can be obtained. The amount of fibrous material, preferably wood pulp, is preferably between 1 and 20% of the solids content in the spread emulsion;
If it is less than 1%, the ability to retain the sprayed coagulant for synthetic resin aqueous emulsion on the ground surface will be poor, and as a result, the effect of strengthening the coating on the ground surface will be insufficient. If the fiber content exceeds 20%, dispersion in an aqueous solution containing a coagulant becomes difficult, a larger amount of coagulating liquid than necessary has to be used, and the emulsion coagulating and fixing layer becomes too soft. It is preferable to use the aqueous solution for coagulation at a concentration of 1 to 20%; if it is less than 1%, the power to coagulate the emulsion is insufficient, and if it exceeds 20%, the coagulation power is strong, but it is necessary for uniformly dispersing it on the ground. Using large amounts becomes uneconomical. The amount of spray liquid is preferably 0.5 to 3 kg per ¹ m2, and 0.5
If it is less than Kg/m ² , it is difficult to uniformly spread it over the entire surface, and if it exceeds 3 Kg/m ² , a large amount will flow down the slope, making it uneconomical. Although the solid content concentration and spray amount of the aqueous synthetic resin emulsion are not particularly limited, a solid content concentration of 3 to 30% and a spray amount of 0.5 to 5 kg/m ² are suitable. Hereinafter, the present invention will be further explained with reference to Examples, but it is of course not limited to the Examples. Examples 1 to 10 and Comparative Examples 1 to 9 Soil from the Sakurajima Bora layer, consisting of volcanic ash and a small amount of pumice, was pounded and hardened in a test container with a surface area of about 0.1 m ² (irradiation angle 30°), and wood pulp was applied to the surface. Immediately after spraying the mixed coagulant-containing aqueous solution, a synthetic resin aqueous emulsion (trade name, Tufftac 120, product of Sanyo Kokusaku Pulp Co., Ltd., solid content concentration 45%, viscosity 90cps, 25℃) is applied.
After diluting the solution appropriately and spraying, the mixture was left outdoors for 5 days, and after drying and fixation, the surface hardness, disintegration properties due to jet water flow, and thickness of the fixed layer were examined. The result is the first
Shown in the table. After drying and fixing, a part of the fixed surface layer was sampled and the surface hardness was measured after immersing it in water for 2 days, and the reduction rate was within 10% in all cases, indicating that a water-resistant fixed layer was formed. Comparative Examples 1 to 1 shown in Table 2
When the wood pulp and coagulant were not used as in Example 9, or when either one of them was absent, the adhesion layer was weak and good water resistance could not be obtained.

【table】

【table】

[Table] Note 1: Based on Note 1 of Table 1.
Note 2: According to Note 2 in Table 1.
Note 3: Coagulant is sulfuric acid.

Claims (1)

[Scope of Claims] 1. A soil surface characterized in that an aqueous solution in which a coagulant for a synthetic resin aqueous emulsion and a fiber substance are mixed is uniformly spread on the soil surface in advance, and then a synthetic resin aqueous emulsion is immediately spread. Protection methods. 2. The soil surface protection method according to claim 1, wherein the coagulant is a water-soluble salt of a divalent metal. 3. The soil surface protection method according to claim 1, wherein the coagulant is a water-soluble salt of a trivalent metal. 4. The soil surface protection method according to claim 1, wherein two or more types of coagulants are used in combination. 5. The soil surface protection method according to any one of claims 1 to 4, wherein the fibrous material is wood pulp.