JPS593502B2 - Stabilization of soil surface layer, greening method - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a method for stabilizing and greening the surface soil of roads, rivers, etc., and slopes such as mountainsides, and is particularly applicable to slopes mixed with rocks that are difficult to green. It is related to applicable construction methods.

35 Conventionally, the seed soil spraying method, the vegetation hole method, and the vegetation bag method have been mainly adopted as methods for greening slopes containing rocks.

Among these methods, the seed soil spraying method is relatively easy to apply because it allows the use of mechanical force, and it is possible to cover the entire slope uniformly and quickly, but it lacks adhesion to the surface layer, allowing plants to take root. In many cases, it dried and fell off before the construction effect was visible, or it was washed away by rain.

In order to prevent erosion, methods such as trench cutting and seeding and soil spraying have been proposed, but this method is limited to cases where the soil is suitable for trench cutting. On the other hand, in the case of the vegetation hole method and the vegetation bag method, greening is highly certain, but requires a considerable amount of manpower and costs a lot of money.

Furthermore, these methods are still partial seeding methods, and it takes quite a long time to reach full coverage, and during that time,
It is necessary to take measures to prevent erosion of the space. In addition, these cases are also limited to soils that can be drilled and grooved. Furthermore, one drawback of all of the seed soil spraying methods, the vegetation hole construction method, and the vegetation bag construction method is that they are unsuitable as measures to prevent rockfalls on relatively fragile foundations such as weathered soft rock slopes. In order to prevent this, it is essential to use net together.

The inventor of the present invention has eliminated these drawbacks of the conventional technology and has developed a method that uses mechanical force to uniformly sow seeds over the entire surface at a relatively low cost.Moreover, it has high adhesion to the surface layer even on slopes with rocks, and in addition, it can prevent rockfall. As a result of various studies, we developed a multilayer construction method in which a mixed dispersion of cellulose fiber, vinyl resin aqueous emulsion, and water is sprayed onto cement or/and hemihydrate gypsum as the first layer. We have discovered that the spraying method is effective and have arrived at the present invention. This first layer serves as a kind of anchor that acts as an adhesive between the second layer, which is the germination bed, and the surface layer of the slope.In addition, this first layer also plays the role of preventing rockfall. This is an important layer. The properties required for this first layer are that it has high adhesion strength with the particles constituting the five layers on the inclined surface, is water resistant, and is resistant to the formation of cracks and peeling due to freezing and thawing of water present in the cracks of the base. It must be flexible enough to prevent damage, be soft enough to allow plant roots to penetrate, and have high water retention, water permeability, and air permeability.It must also have fluidity suitable for spraying work. Furthermore, it has good adhesion to the surface layer when sprayed. When cement is used alone as this first layer, it has insufficient flexibility, water retention, water permeability, air permeability, fluidity, and adhesion, and is completely unsuitable as a greening base material, especially in terms of softness. .

When gypsum hemihydrate is used alone, there is also a problem in terms of water resistance. When a vinyl resin aqueous emulsion is further used in cement or/and hemihydrate gypsum, adhesive strength, water resistance, water retention, and fluidity are improved, but flexibility and adhesion are still not sufficient, and the soft is not improved.

Furthermore, water permeability and air permeability are rather reduced. cement or/
When cellulose fiber is used in combination with gypsum hemihydrate, the softness, water permeability, and air permeability are greatly improved, and the flexibility and adhesion are also increased to a certain extent, but the adhesive strength and water resistance are significantly reduced. The fluidity is also poor. On the other hand, systems using cellulose fibers and vinyl resin aqueous emulsions have problems with water resistance and cannot exhibit enough strength to prevent rockfall.

However, when cement and/or gypsum hemihydrate are further used in combination with cellulose fibers and a vinyl resin aqueous emulsion, the synergistic effects of these elements satisfy all of the requirements of the first layer. Eventually, vegetation became possible.

This fact shows that when seeds are conventionally sown on top of a cement or gypsum layer,
This was completely unexpected from the common sense that even if the seeds germinate, the growth conditions are extremely poor.

The typical cement used for stringing is ordinary Portland cement, but any hydraulic cement such as fly ash cement, blast furnace cement, early strength cement, etc. can be used depending on the construction conditions.

Whether to use cement, hemihydrate gypsum, or a combination of both can be arbitrarily determined depending on the pH at which plants can grow and the soil quality of the target slope.

The cellulose fiber may be in the form of fibers, fluff, or powder, as long as it is a cellulose-based fiber with water absorbing properties.

Examples of aqueous vinyl resin emulsions include polyvinyl acetate, polyacrylic acid ester, ethylene vinyl acetate copolymer, as long as they have good miscibility with cement or hemihydrate gypsum.
Any known aqueous vinyl resin emulsion such as vinyl acetate acrylic copolymer, acrylic styrene copolymer, styrene butadiene copolymer, etc. can be used.

Note that vinyl resin aqueous emulsion refers to a vinyl resin with a purity of about 30 to 60 (Fb) obtained by performing so-called emulsion polymerization using water as a medium, but in the present invention, the purpose is Therefore, regardless of the presence or absence of a film-forming agent, it is necessary to have the ability to form a film by evaporating water under the conditions of use.The blending ratio of the components constituting the first layer and the layer thickness of the first layer are subject to change. soil quality of the slope,
It can be selected arbitrarily depending on the type of seeds and the construction period, but the generally preferred mixing ratio is 1 part cement when using cement.
00 parts by weight, 30 to 400 parts by weight of cellulose fiber, 2 to 50 parts by weight of vinyl resin aqueous emulsion.
parts by weight, in the case of using gypsum hemihydrate, 10 to 40 parts by weight of cellulose fiber, 2 to 50 parts by weight of aqueous vinyl resin emulsion, cement and gypsum hemihydrate to 100 parts by weight of gypsum hemihydrate. When used together, add 20 to 20 parts of cellulose fiber to 100 parts by weight of cement and gypsum hemihydrate.
0 parts by weight, vinyl resin aqueous emulsion purity equivalent 2-5
It is preferable that the amount is in the range of 0 parts by weight, and the layer thickness is usually 3 to 7 mm. It is desirable that the amount of water used be as small as possible without impairing spraying workability.

As the first layer constituent components in the construction method of the present invention, known thickeners, dispersants, setting accelerators, and retarders may be added as auxiliary agents as necessary. It is also possible to add bulking materials such as , waste tire scrap, etc. to the cement or/and hemihydrate gypsum.

If the amount of such filler exceeds 3 times the amount, the water resistance will be considerably reduced, so it is preferable to use up to 3 times the amount.

Furthermore, it is also possible to add fertilizer components. The second layer spray material is a mixed dispersion containing a small number of co-cellulose fibers and a vinyl resin aqueous emulsion, and the vinyl resin aqueous emulsion used in this layer does not necessarily need to be miscible with cement or hemihydrate gypsum. . The blending ratio of the cellulose fibers and the aqueous vinyl resin emulsion in the second layer can be arbitrarily selected depending on the type of seeds and the time of application, but the generally preferred blending ratio is 100% of the cellulose fibers.
Purity of vinyl resin aqueous emulsion converted to parts by weight 2
~5 parts by weight.

The thicker the second layer, the better, and it is desirable to spray it several times as necessary. The second layer is mainly composed of cellulose fibers, and the aqueous vinyl resin emulsion improves the adhesion between the cellulose fibers and the first layer, especially when wet, and also improves the adhesion between the cellulose fibers and the first layer. It also has the effect of increasing the adhesion of the third layer and preventing it from washing away due to heavy rain. As components of the second layer spray material, known greening base materials such as fertilizers, curing agents, thickeners, and soil may be added as necessary.

The third layer spraying material consists of a greening base material mixed dispersion containing a small amount of co-seeds and fertilizer, and any known greening base material may be used.

It is best to spray the second layer when the previously sprayed first layer begins to condense, and it is most reliable to spray the third layer after the second layer has dried. The period is not particularly limited.

The present invention will be explained below with reference to Examples.

Example 1 A composition to form the first layer prepared in the proportions shown in Table 1 was sprayed onto a sloped surface of weathered granite with a slope of about 35 mm.

Claims (1)

[Claims] 1. A soil surface stabilization and greening method characterized by sequentially spraying the following spraying materials on the ground surface. b) A mixed dispersion liquid containing at least the first layer spraying material, cement or/and hemihydrate gypsum, cellulose fiber, and a vinyl resin aqueous emulsion. (b) Second layer spray material A mixed dispersion liquid that does not contain a hydraulic substance and also contains at least a cellulose fiber and a vinyl resin aqueous emulsion. c) Third layer spraying material A greening base material mixed dispersion liquid containing at least seeds and fertilizer. 2. The soil surface layer according to claim 1, wherein the first layer has a small amount of sprayed material, and contains 100 parts by weight of co-cement, 30 to 400 parts by weight of cellulose fiber, and 2 to 50 parts by weight of vinyl resin aqueous emulsion, calculated as pure content. stabilization and greening methods. 3 The first layer spraying material is less, 100 parts by weight of gypsum hemihydrate,
The soil surface stabilization and greening method according to claim 1, which contains 10 to 40 parts by weight of cellulose fiber and 2 to 50 parts by weight in terms of pure vinyl resin aqueous emulsion. 4 The first layer has a small amount of spray material, a total of 100 parts by weight of cement and gypsum hemihydrate, and 20 to 200 parts of cellulose fiber.
Parts by weight, converted to vinyl resin aqueous emulsion purity 2 to 50
The soil surface stabilization and greening method according to claim 1, which contains parts by weight. 5. The soil surface stabilization and greening method according to claim 1, wherein the vinyl resin aqueous emulsion of the first layer spray material is polyvinyl acetate. 6. The soil surface stabilization and greening method according to claim 1, wherein the vinyl resin aqueous emulsion of the first layer spray material is a polyacrylic ester. 7. The soil surface stabilization and greening method according to claim 1, wherein the vinyl resin aqueous emulsion of the first layer spray material is an ethylene-vinyl acetate copolymer. 8. The soil surface stabilization and greening method according to claim 1, wherein the vinyl resin aqueous emulsion of the first layer spray material is a vinyl acetate acrylic copolymer. 9. The soil surface stabilization and greening method according to claim 1, wherein the vinyl resin aqueous emulsion of the first layer spray material is an acrylic styrene copolymer. 10. The soil surface stabilization and greening method according to claim 1, wherein the vinyl resin aqueous emulsion of the first layer spray material is a styrene-butadiene copolymer.