JPS6316435B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention provides a method for preventing collapse of soil on sloped land surfaces, etc.
In particular, the present invention relates to a method for preventing the collapse of the ground, such as a volcanic ash deposit containing pumice, which easily collapses due to running water, and a large amount of water causes a debris flow to flow down, causing a major disaster. [Prior Art] Soil collapse prevention has been conventionally carried out using greening methods or surface coating agent spraying methods. However, the surface layer may shift and be washed away when the vegetation is not fully grown or flourishing, or the surface coating material may not be spread uniformly and may crumble from that area due to uncoated areas, or the water resistance of the coating material may be affected. Because of the poor quality, the adhesion is often reduced by rainwater, resulting in water being washed away. Therefore, prevention of soil collapse using greening methods is limited to areas suitable for vegetation where there is always a suitable amount of moisture, the soil PH is close to neutral, and major collapse does not occur. . In addition, the surface coating agent spraying method is only used in places where it can be expected to have a short-term washout prevention effect, or for the purpose of preventing flying sand. Therefore, in general, the only reliable methods of construction are large-scale civil engineering work such as protective nets, cement mortar spraying, and the construction of protective walls. [Problems to be solved by the invention] As a result of intensive research into preventing collapse in areas where current greening methods and surface coating spraying methods are less effective, the present inventors have developed a synthetic polymer with good water resistance and excellent permeability. It has been discovered that this object can only be achieved very economically by dispersing an aqueous emulsion of the substance with a dispersion of light colored wood pulp, shredded paper or colored pigments. In other words, in order to prevent collapse and washout, the surface layer 1
It is desirable to fix the soil to a thickness of 5 mm or more, preferably 5 mm or more, and make the strength of the fixed layer wet with water 20 or more on the Yamanaka hardness tester. It has been found that although slight unevenness in sticking thickness is acceptable, it is necessary to spray the aqueous emulsion over the entire surface, and if there are areas that are not sprayed, a fatal problem will occur. [Means for solving the problem] The gist of the present invention is that the particle size is 0.02 to 0.5μ,
A water-resistant synthetic resin aqueous emulsion with a JISK-6828 water drop test value of 1 minute or more and a viscosity of 5 cps or less at a concentration of 5% is sprayed on the soil surface and penetrated.
In order to strengthen the soil surface by drying and fixing, light colored wood pulp, shredded paper pieces or colored pigments are sprinkled on the water-resistant synthetic resin water-based emulsion to uniformly spread the water-resistant synthetic resin water-based emulsion on the soil surface. The present invention is a method for preventing soil collapse, which is characterized by adding and dispersing 0.1 to 5% to a liquid in advance, thereby achieving the intended purpose. [Function] Synthetic polymer aqueous emulsions with good water resistance include acrylic esters, methacrylic esters, styrene copolymers, and vinyl chloride copolymers, which remain strong even when wet after drying. It is necessary that the aqueous synthetic resin emulsion exhibits little deterioration, and in particular has a water droplet test value of 1 minute or more according to JISK-6828. Therefore, materials with poor water resistance such as vinyl acetate are not suitable for the purpose of the present invention. In addition, in order to increase the penetration and fixation thickness,
The diameter of the copolymer particles is in the range of 0.02 to 0.5μ, the viscosity of the emulsion is low, specifically, the viscosity at 5% concentration is 5 cps or less, and the emulsion does not separate and solidify before being sprayed and penetrated. It needs to be sufficiently stable. Furthermore, in order to dry and solidify under natural conditions after spraying, the minimum film forming temperature of the polymer emulsion is preferably 20°C or lower; on the other hand, if it is too low, the film will become too soft and the strength will be too low, so it is recommended that it is -5°C or higher. preferable. On the other hand, in the present invention, it is most important to uniformly spread the liquid over the entire surface of the soil, and for this purpose, it is necessary to easily check the sprayed area and amount from a distance. Of course,
This is especially important for aerial spraying using helicopters. As a result of various studies in this regard, we have found that colored pigments such as white, yellow, orange, or other light-colored wood pulp, finely cut pieces of similarly colored paper, or finely divided calcium carbonate are used by uniformly dispersing them in the emulsion. was found to give the best results. In particular, in the case of the wood pulp and paper pieces used in the present invention, it not only makes the amount of dispersion uniform, but also creates a strong protective film on the surface after the emulsion is sprinkled on the ground and dries, further improving the effect of preventing collapse. It is advantageous because it has the function of The optimum amount of the above liquid to be sprayed varies greatly depending on the target area, but for example, in areas where volcanic ash is the main ingredient, 1 to 5 doses of synthetic polymer emulsion with a solid content concentration of 5% are required per 1 m ² . If it is less than 1, the effect is insufficient, and if it is more than 5, the amount that is washed away without permeating increases, which is uneconomical. Pulp and/or paper pieces or colored pigments added at the same time need to be 0.1 to 5% by weight of the liquid; if it is less than 0.1%, it will be difficult to confirm the spraying location and amount, and if it is more than 5%, the spraying will not be possible. It becomes difficult. [Example] The present invention will be explained below with reference to Examples, but of course the present invention is not limited only by the Examples. Example 1 The soil of the Sakurajima Bora layer consisting of volcanic ash and a small amount of pumice was compacted, the liquid viscosity was 1.5 cps, the solid content concentration was 5%, the particle size was 0.08 to 0.20 μ, the minimum film forming temperature was 10°C, and the water drop test was conducted at 30°C.
Add 0.2% by weight of bleached wood pulp as a dry matter to a butyl acrylate and styrene copolymer emulsion with a dry weight of ² or 4 minutes per square meter, and add 0.2% by weight of bleached wood pulp to the emulsion. was dispersed. After being completely dried and fixed at 25°C after spraying, the surface hardness, disintegration property due to jet water flow, and thickness of the fixed layer were examined. The results are shown in Table 1 (Hardness was measured using a Yamanaka hardness tester.)

【table】

[Table] Example 2 After adding and dispersing 0.2% of 66 g of high-quality paper cut into 5 mm squares into the same emulsion as in Example 1 (dispersing with gentle stirring to avoid disintegrating the paper pieces), a dispersion type nozzle was used. Similar to Example 1, the geological
The cubed high-quality paper was sprayed onto a 40° inclined surface (height: 10 m, length: 20 m) so that the distribution density was the same. It was very easy to identify unsprayed areas and confirm the amount sprayed. The surface hardness after natural drying, changes in the ground surface due to water injection, adhesion thickness, and others are as shown in Table 2, indicating that the collapse prevention effect is large.

[Table] Reference example Same Sakurajima Bora layer as in Example 1, without adding wood pulp or paper pieces to a vinyl acetate copolymer emulsion with a minimum film forming temperature of 5°C, a particle size of 0.5 to 2μ, a concentration of 5%, and a viscosity of 15 cps. The particles were sprayed at a rate of 2/m ² and 4/m ² . This product was completely dried at 25°C and the same test as in the example was conducted. At the same time, a test was also conducted in the same way on a device in which no liquid was sprayed at all. The results are shown in Table 3.

〔Effect of the invention〕

According to the method of the present invention, the particle size is 0.02 to 0.5μ, JISK-
A water-resistant synthetic resin emulsion with a water droplet test value of 6828 for 1 minute or more and a viscosity of 5 cps or less at a concentration of 5% is sprayed on the soil surface and dried and fixed, resulting in water resistance that penetrates into the soil surface with a large thickness. A reinforcing layer can be formed. In addition, by pre-adding and dispersing brightly colored wood pulp, paper chips, or colored pigments in the above water-resistant synthetic resin emulsion, it is possible to spread the above-mentioned water-resistant synthetic resin emulsion on the soil area and the amount of spraying from a distance. It can be easily checked and the purpose of uniform dispersion can be achieved.

Claims (1)

[Claims] 1. A water-resistant synthetic resin aqueous emulsion with a particle size of 0.02 to 0.5 μ, a JISK-6828 water drop test value of 1 minute or more, and a viscosity of 5 cps or less at a concentration of 5% is sprayed on the soil surface and permeated, and the soil surface is dried and fixed. For strengthening, add 0.1% of light-colored wood pulp, shredded paper pieces, or colored pigments to the water-resistant synthetic resin aqueous emulsion spray solution to uniformly spread the above-mentioned water-resistant synthetic resin aqueous emulsion on the soil surface. A method for preventing soil collapse, characterized by adding and dispersing ~5% in advance.