JP3529200B2 - How to prevent turbid water - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for preventing the generation of turbid water, and more particularly to a method for generating turbid water by entraining fine soil particles when rainwater flows down the ground surface during rainfall. The present invention relates to a method for preventing generation of turbid water. [0002] For example, when rainfall occurs during earthworks at a construction site such as a road, a house building, a golf course, etc., stormwater is generated by rainwater flowing down the surface of the excavation ground while entraining fine soil particles. This turbid water flows down into urban areas, paddy fields, roads, lakes and marshes, damaging these environments, and in places where the flow velocity decreases, the fine sediment carried by the turbid water sinks and accumulates in various places even after the turbid water flow has stopped. The destruction of the environment due to turbid water has become a social problem. [0003] Such problems are caused by landslide areas, railways,
It has also been pointed out that various other ground surfaces, such as road slopes, through which rainwater flows down during rainfall. [0004] As a countermeasure to prevent the generation of turbid water from the ground surface, for example, the following method has conventionally been implemented. (1) The ground surface is compacted by a roller or the like. (2) Cover the ground surface with a waterproof sheet or film. (3) Spraying a water-reactable polyurethane system on the ground surface. (4) A reservoir is created so that all turbid water flowing down collects in this portion, and fine soil particles are settled in the reservoir. [0005] However, in the above method (1), it takes a lot of labor and time to perform the compacting operation with the roller each time according to the weather,
In particular, it is difficult to carry out the method on an earth work site, and it is not efficient at the earth work site because the compacted ground surface must be excavated again. In the method (2), it is easy to cover a ground surface having a small area, but it is difficult to cover a ground surface having a large area. In the method (3), a spraying machine is special, and the reacted gel body is not only destroyed by the sun and its effect is diminished, but also remains after the weathering, resulting in environmental problems. The method of (4) does not prevent the generation of turbid water itself. In addition, in order to create a reservoir, it is necessary to have suitable topography, and when rainfall is heavy, the entire amount is stored in the reservoir. There are drawbacks that cannot be completely solved, and in particular, when the method is adopted in an earth construction site, there is a case that backfilling and leveling may be performed again after the construction, and there is a problem that the work is troublesome. Therefore, none of the conventional methods can be said to be an economical and effective preventive measure, and a new measure for preventing the generation of turbid water is desired. The present inventors have proposed a simple alternative to the above method for preventing the generation of turbid water, by treating fine soil particles of earth and sand constituting the ground surface with a certain kind of water-soluble polymer.
It has been found that it is possible to prevent the generation of turbid water or to remarkably reduce the amount of sediment carried by the falling water by avoiding the entrainment of fine soil particles as the rainwater flows down the ground surface as much as possible. That is, the present invention provides a method for preventing the generation of turbid water, which has a configuration which can be easily and quickly implemented, and which can surely prevent generation of turbid water from the ground surface on which rainwater flows. It is the purpose. [0009] A method for preventing the generation of muddy water according to the present invention has been made to achieve the above object.
An aqueous solution having a solid content of 0.1 to 5.0% containing cationic guar gum, sodium alginate, or a water-soluble polymer selected from nonionic or cationic polyvinyl alcohol on the ground surface where rainwater flows down during rainfall. 0.2 to 5 l / m ² to prevent rainwater from flowing down. DETAILED DESCRIPTION OF THE INVENTION The aqueous polymer used in the present invention includes, for example, methylcellulose (MC), hydroxyethylcellulose (HEC), and hydroxyethylcellulose (HEC) as water-soluble polymers that enhance the aggregation effect of fine soil particles. Cellulose derivatives such as ethyl methyl cellulose (HEMC), natural gums such as guar gum, xanthan gum, gum arabic,
It is preferable to use polyvinyl alcohol, a cation or anion-modified product thereof, or sodium alginate as a water-soluble polymer that forms a coating on the surface of soil to prevent generation of turbid water. [0011] Then, among the water-soluble polymers of these, use of cationic guar gum, sodium alginate or nonionic or cationic vinyl alcohol. In addition, a cationic resin emulsion, a water-repellent silicone resin, a fluororesin,
An emulsion type of silicone fluororesin can be used in combination. The amount of the water-soluble polymer is 0.1 to 5.0% by solid content in the spray liquid. This can be sprayed on the ground surface using, for example, a conventional aqueous solution spraying apparatus conventionally used for spraying pesticides or liquid fertilizers. The amount of the water-soluble polymer sprayed on the ground surface is appropriately designed in consideration of the dry state of the ground surface to be applied and the particle size of the earth and sand, the surface smoothness, etc., but the cationic guar gum containing the above solid content range or 0.2 to 5 l of sodium alginate solution
/ ^{M 2} about you spraying. When it is less than 0.2 l / m ² , the effect of coagulating fine soil particles cannot be sufficiently obtained, and when it is more than 5 l / m ² , the effect of preventing the generation of turbid water is particularly improved. Not only that, but also the drying time becomes unnecessarily long, which has the opposite effect. The ground surface to be sprayed is desirably dried until the free water disappears, and then sprayed. It is desirable that the spraying be performed at least 24 hours before the rainfall predicted by the weather information or the like. However, depending on the circumstances, the spraying can be performed immediately before the rainfall. As the condition of the ground surface where the spraying is carried out, a relatively smooth and hard surface is good, so it is desirable to compact by a roller or the like as a pretreatment and spray after flattening, but it is desirable to spray without performing the pretreatment. It is also possible. The method for preventing the generation of turbid water according to the present invention will be described in more detail with reference to examples and comparative examples, but the present invention is not limited to these examples. In the examples, parts and% indicate parts by weight and% by weight, respectively. <Embodiment 1> As shown in FIG.
A sprinkling pipe 2 is placed at the top of a sediment bed 1 having a gradient of 0 cm, a width of 50 cm, a thickness of 8 cm, and a slope of 4: 1.
An experimental apparatus connected to a 20-liter plastic tank 4 through the above was made, and a Kanto loam 5 having a natural water content of about 20% was laid on the upper surface of the earth and sand bed 1 with a thickness of about 5 cm. After laying earth and sand, cationic guar gum containing 0.5% solids (trade name: each) was placed on the surface of sample I, which was leveled evenly with a rake, and sample II, which was solidified with a 5 kg iron roller. Aqueous solution (Jaguar CP-13 manufactured by Sansei Co., Ltd.) was sprayed at 1.0 l / m ² . After 24 hours, 5 l / m ² (spraying time: 5 minutes) of water is sprinkled through the water sprinkling pipe 2, and the flowing water is collected in the poly-tank 4 to determine the turbidity of the water,
The amount of runoff was measured. In addition, in order to prevent the whole earth and sand from slipping down on the surface of the earth and sand floor 1, a weir having a height of 1 cm is provided every 20 cm. The turbidity was measured using an ANALITE turbidimeter (manufactured by Central Science Co., Ltd.) at the center of the water flowing into the plastic tank 4. The unit is m in kaolin conversion.
g / l (ppm), and the turbidity of water is 0 ppm in this method.
become. Example 2 Samples I and II prepared using the experimental apparatus shown in FIG. 1 under exactly the same conditions as in Example 1
Cationic hydroxyethylcellulose containing 1.0% solids on the surface of the product (trade name: Katinal HC-200)
1 l / m ^{2 of an} aqueous solution (manufactured by Toho Chemical Industry Co., Ltd.) was uniformly dispersed. After a lapse of 24 hours in the same manner as in Example 1,
5 l / m ² of water was sprinkled over 5 minutes, and the flowing water was collected in a plastic tank 4 to measure the turbidity of the water and the amount of sediment discharged. Example 3 Using the experimental apparatus shown in FIG. 1, sodium alginate (trade name: 0.1%) containing 0.1% solids on the surface of Samples I and II prepared under exactly the same conditions as in Example 1 1.5 l / m ^{2 of} aqueous solution of sodium alginate (manufactured by Kimitsu Chemical Co., Ltd.) was uniformly sprayed. Example 1
After a lapse of 24 hours in the same manner as described above, 5 l / m ²
Water for 5 minutes, and the flowing water
And measured the turbidity of water and the amount of sediment runoff. Example 4 Using the experimental apparatus shown in FIG. 1, a sedimentary red soil 5 having a natural water content of about 20% was laid in a thickness of about 5 cm instead of the Kanto loam. Cationic polyvinyl alcohol containing 2.0% solids on the surface of samples I and II (trade name: C-20, manufactured by Shin-Etsu Chemical Co., Ltd.)
An aqueous solution of 1 l / m ² was evenly sprayed. After a lapse of 24 hours as in Example 1, 5 l / m ² of water was passed through sprinkler tube 2 for 5 hours.
Water was sprayed over a period of minutes, and the flowing water was collected in a plastic tank 4 to measure the turbidity of the water and the amount of sediment discharged. <Comparative Example 1> Using the experimental apparatus shown in FIG. 1, the surfaces of untreated samples I and II made of Kanto loam prepared under exactly the same conditions as in Examples 1 to 3 were passed through a sprinkler tube.
l / m ² of water was sprinkled over 5 minutes, and the flowing water was collected in a plastic tank 4 to measure the turbidity of the water and the amount of sediment discharged. <Comparative Example 2> Using the experimental apparatus shown in FIG. 1, 5 l of untreated samples I and II made of sedimentary red soil prepared under exactly the same conditions as in Example 4 were passed through the sprinkling pipe 2.
/ M ² of water was sprinkled over 5 minutes, the flowing water was collected in a plastic tank 4, and the turbidity of the water and the amount of sediment discharged were measured. The experimental results of Examples 1 to 4 and Comparative Examples 1 and 2 are shown in Table 1 below. [Table 1] As is clear from the results shown in the above table, the amount of sediment runoff from the ground surface treated with cationic guar gum, sodium alginate and cationic polyvinyl alcohol as water-soluble polymers is the same as the runoff from the untreated ground surface. It was found that the turbidity of the water flowing down was extremely low compared to the amount of sediment. As described above, the method for preventing the generation of turbid water according to the present invention uses the method of selecting from cationic guar gum, sodium alginate, nonionic or cationic polyvinyl alcohol on the ground surface where rainwater flows down during rainfall. When rainwater flows down the ground surface by a simple and quick method of spraying the water-soluble polymer to be applied as an aqueous solution having a solid content of 0.1 to 5.0% at 0.2 to 5 l / m ^2. As a result, it is possible to prevent turbid water from being generated from the ground surface where the rainwater flows down, and to significantly reduce the amount of sediment carried by the rainwater. Accordingly, the present invention prevents the generation of turbid water due to rainfall on the ground surface where rainwater flows down, such as an earthworks site, a landslide area, a railroad or a road slope, and destroys the surrounding environment due to turbid water. It is suitable for preventing collapse of the ground.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory diagram of an experimental device used in Examples and Comparative Examples.

   ────────────────────────────────────────────────── ─── Continuation of front page    (72) Inventor Isao Shirataki               28 Nishifukushima, Oku-ku, Niigata Prefecture               1 Shin-Etsu Chemical Co., Ltd.               Inside the hall (72) Inventor Kiyoshige Nishibayashi               4-640 Shimoseito, Kiyose-shi, Tokyo Stock               Obayashi Technical Research Institute (72) Inventor Takayuki Ueno               4-640 Shimoseito, Kiyose-shi, Tokyo Stock               Obayashi Technical Research Institute                (56) References JP-A-57-59983 (JP, A)                 JP-A-53-125311 (JP, A)                 JP-A-1-207384 (JP, A)                 JP-A-61-23682 (JP, A)                 JP-A-5-32970 (JP, A)                 JP-A-48-68715 (JP, A)

Claims (1)

(57) [Claims 1] A solid content containing a water-soluble polymer selected from cationic guar gum, sodium alginate, nonionic or cationic polyvinyl alcohol on the ground surface where rainwater flows down during rainfall. A method for preventing generation of muddy water, which comprises spraying 0.2 to 5 l / m ² as an aqueous solution having a volume of 0.1 to 5.0% to prevent rainwater from flowing down.