JPH06116561A - Soil erosion preventing agent and execution method for preventing soil from eroding - Google Patents

Abstract

PURPOSE:To obtain a soil erosion preventing agent capable of uniformly mixing with soil, keeping a stable dispersion state when its mixture is converted into a slurry, thereby forming a consolidated layer having moderate air permeability and flexibility and providing excellent soil erosion preventing and vegetational promoting effects and an execution method for preventing soil from eroding. CONSTITUTION:The soil erosion preventing agent is obtained by using microencapsulated asphalt particles 9. This soil erosion preventing agent is mixed with a soil dressing 7 and seeds 10 to form a mixture slurry, which is then sprayed on a normal surface 1 to form a consolidated layer 16.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a soil erosion preventive agent and a soil erosion preventive method suitable for preventing erosion on soil surfaces, particularly slopes.

[0002]

2. Description of the Related Art Conventionally, as a method for preventing erosion of slopes, there has been a method of mixing soil with asphalt emulsion or polyvinyl acetate emulsion and, if necessary, a water-soluble polymer substance and spraying the mixture onto the slope. It is known (for example, Japanese Patent Publication No. 47-3305). In this method, an asphalt emulsion prepared by emulsifying asphalt in water with an emulsifier and a stabilizer is prepared in advance, this emulsion is mixed with soil on site, and the mixture is sent by a slurry pump and sprayed on the slope with a compressed air gun. I have to.

However, since the asphalt emulsion is used in this method, the handling is complicated, there is a risk of freezing in winter, it is difficult to maintain a stable emulsified state, and it is difficult to form a complete erosion preventive layer. There is a problem that is.

On the other hand, a method has also been proposed in which a vegetation base material containing a water-soluble polymer substance is sprayed on the slope to effect vegetation (for example, Japanese Examined Patent Publication No. 48-11604).

However, this method has a problem that soil erosion is not completely prevented until a vegetation layer is formed and the vegetation base material is easily washed away by wind and rain.

[0006]

The object of the present invention is easy to handle, there is no fear of freezing in winter, it can be uniformly mixed with soil, and when the mixture is made into a paste or slurry form. By providing a soil erosion inhibitor and a soil erosion prevention method that can maintain a stable dispersed state, thereby forming a solidified layer having appropriate air permeability and flexibility, and obtaining an excellent soil erosion prevention effect. is there.

[0007]

The present invention provides the following soil erosion preventive agent and soil erosion preventive construction method. (1) A soil erosion inhibitor comprising microencapsulated asphalt particles. (2) A soil erosion prevention method characterized by mixing microencapsulated asphalt particles and soil and spraying the mixture onto the soil surface. (3) A soil erosion prevention method characterized by mixing microencapsulated asphalt particles, soil and seeds, and spraying the mixture onto the slope.

The microencapsulated asphalt particles used as the soil erosion preventive agent of the present invention are obtained by coating the asphalt particles with a coating layer and microencapsulating them to form a powder.

As the asphalt, naturally occurring natural asphalt, petroleum asphalt obtained as a petroleum refining residue, artificial asphalt made of petroleum resin and the like can be used, of any origin. As the type of asphalt, any type of asphalt having a high viscoelasticity such as a normal straight asphalt having a high penetration and a hard blown asphalt having a low penetration can be used, but the viscoelasticity is high. It is preferable to use straight asphalt.

The coating layer for coating the asphalt particles blocks the tackiness of the asphalt particles and keeps them dry, and at the time of construction, they are destroyed by mixing with the soil and spraying,
Any material can be used as long as it exposes the asphalt particles, but a material formed of a water-soluble polymer substance is preferable.

Preferred examples of the microencapsulated asphalt particles include asphalt particles coated with amphiphilic particles and a water-soluble polymer substance. This is an asphalt particle, for example a particle size of 5μ
Amphiphilic particles produced from inorganic particles of less than m and microcapsule obtained by coating with a coating layer made of a water-soluble polymer substance.

The above-mentioned amphiphilic inorganic particles are obtained by treating hydrophilic inorganic particles with a lipophilic substance to impart an affinity to both water and an organic solvent. Those having an amphipathic property collect at the interface between water and an organic solvent when added to a mixture of water and an organic solvent and left standing.

As the hydrophilic inorganic particles used as the base material of the above amphipathic particles, a substance which is substantially insoluble in water is preferable. Examples of such particles include oxides such as silicon dioxide, alumina, and titanium dioxide, heavy or light calcium carbonate, carbonates such as magnesium carbonate, kaolin, and the like.
Examples thereof include silicates such as clay and talc, hydroxides such as aluminum hydroxide and magnesium hydroxide, and sulfates such as barium sulfate and calcium sulfate.

These inorganic particles preferably have a particle size of less than 5 μm. Further, these are usually used alone, but may be used in combination of two or more kinds, or may be used by mixing two or more kinds after making them amphipathic.

The lipophilic substance used for the surface modification of the hydrophilic inorganic particles is a substance which forms a hydrophobic portion on the surface of the inorganic particles, for example, a silane compound, a titanate coupling agent, a condensate of dimer acid and polyamine. -Soluble polyamine condensates such as, acrylic acid-based polymers such as copolymers of polyethylene glycol (meth) acrylate with (meth) acrylic acid or fumaric acid, or copolymers thereof, oil-soluble anionic surfactants Examples thereof include hydrophobizing agents or polymeric substances. These may be used alone or in combination of two or more. The amount of lipophilic substance used is 0.05 with respect to the hydrophilic inorganic particles.
It is preferable to add ˜2% by weight.

The amphipathic particles are obtained by bringing the hydrophilic inorganic particles as the base material into contact with a lipophilic substance, filtering and drying. Since the amphiphilic particles thus obtained have both hydrophilicity and lipophilicity, they have an action of maintaining good emulsion stability of the asphalt particles during microencapsulation of asphalt and during use.

The water-soluble polymer substance used for microencapsulation of asphalt is a polymer substance which dissolves in water and forms a film by drying. Those that dissolve in water when contacted with water in the form of a film are more preferable.
Examples of such substances include gum arabic, gelatin, polyvinylpyrrolidone, polyvinyl alcohol, or partial saponification products of polyvinyl acetate, carboxymethyl cellulose, and the like. The amount of these water-soluble polymer substances used may be such that a film can be formed on the surfaces of the asphalt particles and the amphipathic particles, and generally about 5 to 15% by weight based on the solid content thereof. preferable.

In order to produce microencapsulated asphalt particles, asphalt, amphipathic particles and water-soluble polymer substance are dispersed or dissolved in water and mixed by stirring to emulsify. At this time, the amphipathic particles act as a surfactant to emulsify asphalt and maintain good emulsion stability. By filtering this emulsion or drying it with a spray dryer without filtering, powdery microencapsulated asphalt particles can be obtained.

The thus-obtained microencapsulated asphalt particles have a structure in which a layer of amphipathic particles is formed around the asphalt particles and the surroundings are covered with a water-soluble polymer substance. Therefore, even when a straight asphalt having a high penetration is used as the asphalt, the sticky surface of the asphalt is not exposed and is in a dry powder form.

The soil erosion preventive agent of the present invention contains the above-mentioned microencapsulated asphalt, and may consist of only the microencapsulated asphalt or may contain other additives. Other additives include soil aggregating agents, surfactants, cement, sand, gravel,
Examples include soil. The mixing ratio of other additives is arbitrary.

Examples of the soil aggregating agent to be added to the soil erosion inhibitor of the present invention include polymers such as polyethylene oxide, polyacrylamide or a partial hydrolyzate thereof, polyacrylic acid, polyethylene glycol and polyaluminum chloride. Examples include organic or inorganic coagulants.

The soil erosion inhibitor of the present invention, by itself,
Alternatively, it can be prevented from being eroded by wind and rain by applying it to the soil surface by spraying or the like in a state where it is mixed with soil or seeds.

The microencapsulated asphalt particles are
The coating layer is destroyed by mechanical impact such as collision and compression, heating, etc. to expose the asphalt particles, and the exposed asphalt particles adhere to each other to form a solidified layer, which prevents soil erosion. Therefore, although the coating layer is sufficiently destroyed by mixing and stirring with the soil and the like, a compressive force can be applied by further compaction, compaction and the like. When a water-soluble polymer is used, addition of water causes the coating layer to dissolve, exposing the asphalt particles. As the soil to which the soil erosion inhibitor of the present invention is applied, the slope is a typical one, but the surface of the embankment, or the cut portion,
Other soil surfaces may be used.

In the soil erosion control method of the second aspect of the present invention, the mixture of the microencapsulated asphalt and the soil is sprayed on the soil surface to prevent soil erosion. As the soil, any soil such as organic soil (such as bark compost and peat moss), black soil, sandy soil can be used.
Of these, aggregating agents can be used in combination for soils that are difficult to aggregate. In addition to soil as the main component, fertilizer, water retention material, and other additives can be mixed in the soil at an arbitrary ratio. The compounding ratio of the microencapsulated asphalt to the soil is about 1 to ³ kg / m ³ . These formulations are slurried or kneaded with or without water and sprayed onto the soil surface to form a consolidated layer.

In the soil erosion control method of the third aspect of the present invention, a mixture of microencapsulated asphalt particles, soil and seeds is sprayed on the slope to prevent erosion of the slope soil. Any seed can be used as long as it can form a vegetation community for preventing erosion on the slope. The mixing ratio of the microencapsulated asphalt to the soil is the same as above, and the mixing ratio of the seeds is arbitrary. These mixtures are slurried or kneaded with or without water and sprayed on the slope to form a solidified layer.

The solidified layer formed by these erosion prevention methods destroys the coating layer of microencapsulated asphalt particles to expose the asphalt particles, and the exposed asphalt particles partially adhere to each other to form a porous layer. Form a porous asphalt coating layer. Therefore, erosion due to wind and rain is prevented, and since it has appropriate air permeability and flexibility, it does not hinder the growth of plants and facilitates the formation of vegetation communities.

[0027]

EXAMPLES Examples of the present invention will be described below. FIG. 1 is a configuration diagram showing a soil erosion prevention construction method of the embodiment. In the figure, reference numeral 1 is a slope for carrying out erosion prevention construction, and a mesh (lath) 2 is stretched on the surface thereof and fixed by a pile 3.

As one example of the soil erosion prevention construction method, the pump pressure blowing construction method is taken as an example, and the mixing tank 5 of the mixer truck 4 is used.
The soil 7 is sent by the belt conveyor 6 to the micro-encapsulated asphalt particles 9 from the hopper 8 at the same time.
And the seed 10 and water 11 are supplied and mixed to form a slurry. The mixed slurry is transferred from the transfer pipe 13 by the pump 12, and is sprayed onto the slope 1 using the spraying force of the air 15 from the spray gun 14 to form the solidified layer 16 on the slope 1.

As the above-mentioned soil 7, a soil such as black soil to which an additive such as a fertilizer and a water retaining material is added is used. If the soil needs to be aggregated, the aggregate agent 17
Is supplied to the dissolution tank 18 to be dissolved, and the dissolved agglomerating agent liquid 1
9 is added to the slurry in the transfer pipe 13 to aggregate the soil particles in the slurry.

In the above operation, the microencapsulated asphalt particles are in the form of powder, so they are uniformly mixed with the soil. When it becomes a slurry, the water-soluble polymer substance forming the coating layer dissolves and acts as an emulsion stabilizer to stably disperse the asphalt particles. Further, the amphipathic particles act as a surfactant while being adhered to the periphery of the asphalt particles, keeping the asphalt in a dispersed state and uniformly mixing it with the soil and seeds.

When the slurry thus uniformly mixed is sprayed on the slope, the water in the spray layer is absorbed or evaporated on the slope, and the asphalt particles adhere to each other to form a solidified layer. It At this time, if necessary, pressing force may be applied for compaction. When the aggregating agent is added, fine particles in the soil are aggregated to form an aggregate structure.

The solidified layer thus formed has a structure in which asphalt particles are bonded in a porous or meshed form and the soil and seeds are enclosed in the interior, and the soil and seeds are washed away by wind and rain. Is prevented. Further, since it has appropriate air permeability and flexibility, it does not hinder the growth of plants and facilitates the formation of vegetation layers. Further, when the soil aggregating agent is added, the soil particles are retained in the asphalt mesh in a state of an aggregate structure, so that the effect of preventing runoff and the effect of maintaining air permeability are enhanced.

Although the above-mentioned construction method is a pump pressure blowing method, an air pressure feeding method can also be used. That is, a lath is placed on the slope of a bedrock, etc., seeds, fertilizers, organic base materials (such as bark compost and peat moss), and microencapsulated asphalt particles as an erosion inhibitor are mixed in a hard paste and sent by air compressor. It is sprayed on the slope with a gun to form a solidified layer on the slope.

The test results of the examples will be described below. Reference Example 1 Acrylic acid and polyethylene glycol methacrylate were copolymerized at a ratio of 1: 1 (molar ratio), and 1 part of a copolymer having an average molecular weight of 13,000 obtained by neutralizing with ammonia was dissolved in 900 parts of water to obtain calcium carbonate. After adding 100 parts of (average particle size 0.1 micron) and stirring to deposit a copolymer resin on the surface of calcium carbonate, filtration dehydration was carried out with a filter press and drying to produce amphiphilic particles.

15 parts by weight of the amphipathic particles thus obtained are suspended in 100 parts by weight of water and the temperature is kept at 60 ° C. with stirring.
On the other hand, 80 parts by weight of straight asphalt having a penetration of 400 was heated to 140 ° C., and both of them were mixed and emulsified through a homogenizer in equal amounts.

To this emulsion was added a 10% by weight aqueous solution of polyvinyl alcohol having a saponification degree of about 88% so that the amount of polyvinyl alcohol was 5 parts by weight, and the mixture was dried by a spray dryer with stirring to give microcapsules. A dry powder of modified asphalt particles was obtained.

Example 1 (Erosion test) Black soil 50% by volume, bark compost 25% by volume, peat moss 2
The microencapsulated asphalt obtained in Reference Example 1 was added to a mixed soil of 5% by volume at the addition amount shown in Table 1, mixed and compacted (compacting rate 50%), diameter 10 cm, height 10
It was formed into a lump of cm. This was sprinkled with a shower nozzle at a height of 50 cm from the upper side for 12.8 liter / min (equivalent to a rainfall of 1000 mm / hr) for 10 minutes, and the amount of residual soil after collapse was measured. The results are shown in Table 1. For comparison, the same test was performed with and without the asphalt emulsion.

[0038]

[Table 1]

Example 2 (germination test) 20 g / m ^{3 of} seed (creeping let fescue: CRF) and 1.6 kg / m ^{3 of} powdered asphalt as asphalt were added to the soil of Example 1 and mixed. It was compacted (compacting rate 50%) and left outdoors to observe the growth state of CRF. For comparison, the same germination test was carried out when the asphalt emulsion was added as asphalt at 6 kg / m ³ and when it was not added. After 3 months, the plant height is about 45c with no additives and with powdered asphalt.
However, when the asphalt emulsion was added, the plant height was about 35 cm.

Example 3 Water was added to the mixture of Example 2 to form a slurry, and the polyacrylamide partial hydrolyzate was added to the slurry so that the solid content was 0.2 kg / m ³ . When sprayed on the slope with a spray gun, a solidified layer having air permeability and flexibility was formed, and the soil did not run out.

[0041]

Since the soil erosion inhibitor of the present invention contains microencapsulated asphalt particles, it can be uniformly mixed with soil, and at the time of use, the asphalt particles are exposed to form a solidified layer, which causes wind and rain. It is possible to effectively prevent erosion of soil due to.

The soil erosion prevention construction method of claim 2 of the present invention comprises:
Since the microencapsulated asphalt particles are mixed with the soil and sprayed onto the soil surface, the asphalt and the soil can be uniformly mixed, and when the mixture is made into a slurry, a stable dispersed state is maintained, which results in an appropriate amount. By forming a solidified layer having air permeability and flexibility, the soil erosion prevention effect can be obtained.

The method for preventing soil erosion according to claim 3 of the present invention is
Since seeds are further added to the above mixture to form a solidified layer on the slope, it is possible to facilitate formation of the vegetation layer with appropriate air permeability and flexibility, and to obtain an excellent erosion control effect.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a soil erosion prevention construction method of an embodiment.

[Explanation of symbols]

 1 Slope 2 Net 3 Pile 4 Mixer 5 Mixing tank 6 Belt conveyor 7 Soil 8 Hopper 9 Microencapsulated asphalt particles 10 Seed 11 Water 12 Pump 13 Transfer pipe 14 Spray gun 15 Air 16 Solid layer

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Saburo Wakisaka 7-3 Roppongi, Minato-ku, Tokyo Toaido Road Industry Co., Ltd. (72) Inventor Kazuo Sato 6-3 Minami, Toyonan-cho, Toyonaka-shi, Osaka No. 13 Honwa Kagaku Kogyo Co., Ltd. (72) Inventor Chiaki Yamashita 6-3 Minami, Toyonan-cho, Toyonaka-shi, Osaka No. 13 No. 13 Hogwa Kagaku Kogyo Co., Ltd. (72) Inventor Yajima Yashu 3 Nishi-Shinjuku, Shinjuku-ku, Tokyo 4-7 Kurita Industry Co., Ltd.

Claims (3)

[Claims] 1. A soil erosion preventive agent comprising microencapsulated asphalt particles. 2. A method for preventing soil erosion, which comprises mixing microencapsulated asphalt particles and soil and spraying the mixture onto the soil surface. 3. A soil erosion prevention construction method, which comprises mixing microencapsulated asphalt particles, soil and seeds, and spraying the mixture onto a slope.