JP2000291013A - Formation method of greening bed - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a formation method of a vegetation bed excellent in construction efficiency, frozen soil resistance, erosion resistance, consolidation resistance or the like and suitable for plant growing. SOLUTION: In a formation method of a greening bed having higher-mode aggregated structure by mixing muddy basic materials as slurry constituted of a vegetation bed material containing clay mixed with water with aggregation agent as flocculant at a spray nozzle or around the spray nozzle to spray it on the surface to be executed while making it aggregatively react, before the mixing of the muddy basic materials with the aggregation agent, an inorganic silicate compound is added to the muddy basic materials to mix. A reaction regulator for accelerating gelling reaction of the inorganic silicate compound is added to the aggregation agent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vegetation base for revegetation (i.e., revegetation) having excellent workability and excellent erosion resistance, on slopes caused by civil works such as roads, rivers, lands and dams. Base).

More specifically, the present invention has excellent workability on slopes where it is difficult to construct steep slopes, slopes with severe unevenness, etc., has a severe natural environment, and has a more developed vegetation base layer. The present invention relates to a method for forming a greening base on a slope where slope resistance and pressure resistance are required.

[0003]

2. Description of the Related Art Slope formed by civil engineering works such as rivers, lands, dams, roads, etc., is left exposed and eroded by rain, wind, frost, frost damage, snow cover, etc., causing collapse. Therefore, various greening methods for protecting the surface have been implemented and stabilization has been achieved.

[0004] In general, a method of mixing a large amount of a synthetic resin emulsion such as a vinyl acetate emulsion with a base material mainly composed of organic matter such as bark compost and spraying the resulting resin film to stabilize the base by a formed resin film. Also, a method of adding a cement or the like as a consolidating agent to a substrate to stabilize the substrate has been implemented.

[0005] However, these construction methods have a problem that clay, which is most required for a vegetation base, cannot be mixed due to mechanical restrictions of a spraying machine for spraying the base material. As a method of solving these problems, the inventor of the present invention discloses a method for forming a greening base for forming a vegetation base mainly composed of clay, as disclosed in Japanese Patent Publication No. 2-26932, Japanese Patent Laid-Open Publication No. 1-30019, and Japanese Patent Publication No. A construction method described in JP-A-8-16329 and the like has been developed.

According to the prior art of the present invention, a clayey soil having a water retention and fertilizing effect suitable for plant growth is provided with water retention and fertilizing effect of water permeability and air permeability so as to be more suitable for plant growth. A greening base construction method has been proposed, in which a vegetation base layer having a structure having a higher order aggregate structure can be sprayed and formed on a slope. However, for steep slopes, rock slopes with severe irregularities, etc., a greening base creation method with more excellent workability,
The dam lake slope where the basement layer is washed for a certain period of time due to repeated seasonal flooding and dry conditions, and the law of heavy snowfall where there is a concern that the basement layer will be condensed by the heavy load due to snowfall. On construction sites where the natural environment is severe, such as slopes and slopes in cold regions that are susceptible to frost heaviness and freezing, a greening base creation method that is more reinforced and more resistant to erosion, It was wanted.

[0007] On the other hand, the high-order aggregate structure of the vegetation base layer formed by the prior art is maintained mainly by the bonding with the aggregate, and therefore, depending on environmental conditions,
Aggregates, which are organic matter, undergo biodegradation, plants take root,
Before the vegetation basement layer is stabilized by its rooting effect,
There is a problem that the aggregate structure may be collapsed, and in the prior art, the free water separated by the aggregate reaction by the muddy base material and the aggregate agent flows out along the slope as it is,
There is a problem that the adhesion of the formed vegetation base layer to a steep slope or the like is hindered, and construction on such a slope may become difficult. Recently, in order to increase the strength of the base material, the base material is mainly sandy and contains some clay.
A construction method using a cement-based solidifying agent has been proposed.

However, according to such a construction method, a vegetation base layer having a high-order aggregate structure mainly composed of clay suitable for plant growth is not formed, and a hard base layer having a shape close to a single-grain structure is formed. Therefore, germination and growth of plants are often impaired, and it cannot be said that this is a preferable construction method as a growth base.

[0009]

Therefore, the germination of plants,
It has a high aggregated structure containing a large amount of clay soil suitable for growth, has soil properties that do not inhibit germination and growth of plants, and it is difficult to construct a greening vegetation base that can respond to severe natural environments The development of a construction method that can be easily formed on the slope has been desired.

[0010]

Means for Solving the Problems The inventor of the present invention uses a conventional greening base formation method capable of forming a vegetation base layer having a high-order aggregate structure mainly composed of clayey soil which is optimal for growing plants. In addition, the vegetation base layer, which is more excellent in workability for difficult-to-construct slopes and has been created, has been intensively studied in order to develop a construction method in which strength is strengthened and durability is improved. As a result, an alkali metal silicate compound, a mud-like substrate added with an inorganic silicate compound such as colloidal silica,
By spraying a granulating agent solution containing the reaction modifier dissolved together with the granulating agent in the flocculating agent tank in the spray nozzle or at the vicinity of the spray nozzle while spraying, the reaction modifier controls the inorganic silicate compound. Adjust the gelation reaction conditions, improve the workability compared to the conventional greening base construction method, improve the frost heave resistance, and the strength of the formed base layer,
The present invention has been found out a construction method capable of constructing a greening base having a high-order aggregate structure suitable for growing plants while also improving durability.

According to the present invention, a mud-like base material, which is a slurry obtained by mixing a vegetation base material containing clay and water, and an aggregating agent, which is a polymer flocculant, are sprayed at or near a spray nozzle. By mixing and spraying on the construction surface while performing agglutination reaction (hereinafter also referred to as agglomeration reaction),
In the method of forming a greening substrate having a high-order aggregate structure, before mixing the muddy base material and the aggregating agent, adding and mixing an inorganic silicate compound to the muddy base material, and A method for forming a greening base, characterized by adding a reaction modifier for accelerating the gelling reaction of the inorganic silicate compound to the aggregating agent, is provided.

When spraying a greening base material onto a construction surface,
Aggregation reaction is caused by mixing the aggregating agent and the mud-like base material, and a vegetation base having a high-order agglomeration structure suitable for germination and growth of plants can be instantaneously formed. At this time, free water separated by the aggregation reaction is generated in the muddy substrate. In the present invention, the water thus generated is contained in a silicate gel formed from an inorganic silicate compound such as an alkali metal silicate and colloidal silica by the action of a reaction modifier described below. To make the base layer plastic and prevent freezing, and added silicate compound, aluminum-based compound contained in the muddy base material,
By the reaction between the calcium compounds, etc., the above-mentioned high-order aggregate structure can be strengthened in strength, and therefore, the workability, frost heaving resistance, erosion resistance, compaction resistance, etc. are excellent, and plant growth A suitable vegetation base is created.

As a mud-like base material for instantaneously forming a higher-order aggregate structure, a soil material, a stabilizer, a curing material and a fertilizer are usually used. These are mixed with the aggregating agent in the nozzle and near the nozzle, and sprayed on the slope, instantly terminates the agglomerated reaction, separates free water, plasticizes, and forms a higher-order agglomerated structure. Adheres stably to the slope. The soil material used here is a mixture of a clay loam soil mainly containing clay and silt containing a silica-alumina-based compound and a calcium-based compound, and a fully-ripened compost (for example, Jetsoil manufactured by Saikko Co., Ltd.). ), The stabilizer is a derivative of natural vegetable oils and fats, and is used for maintaining appropriate water for the growth of plants and imparting erosion resistance by the balance of appropriate hydrophilicity and lipophilicity in the formation base layer. The fertilizer / curing material is used to supply the fertilizer component to the base layer and to make the fertilizer component uniform in the mixing tank during the spraying operation. (For example, manufactured by Aiko Corporation: Jet Seed).

The mud-like base material containing these materials is uniformly mixed in a mixing tank and then sent by a slurry pump.
In the nozzle or near the nozzle, it is mixed and sprayed with the aggregating agent (for example, Soil Floc, manufactured by Aimitsu Co., Ltd.) which is melted in a separate tank. A vegetation base layer having a high-order aggregate structure is formed on the spray slope.

The formed vegetation base forms voids of various sizes, and has a structure excellent in water retention, fertilization, air permeability, and water permeability, and becomes a base suitable for plant growth. The structure of the vegetation base formed in this way is composed of the aggregated agent, the clay component in the muddy base material, the aggregate structure of the high-order bridged muddy base material formed by humic substances, and the stabilizer. Is maintained by the binding force and water repellency of the resin component contained in the herb, and the rooting effect of herbs germinating and growing from the beginning of construction.

Furthermore, an inorganic silicate compound such as an alkali metal silicate compound and colloidal silica is added to a mud-like base material capable of forming a vegetation base layer having a higher aggregated structure, and the aggregated material is added to the aggregate dissolving tank. By dissolving the reaction modifier together with the granules and mixing the two liquids in and near the nozzle, the degree of plasticization is higher than in the case where the hydrous silica gel is not formed even on difficult-to-install slopes It has high adhesiveness to the ground and can be easily constructed, has excellent frost heaving resistance, and has a high-order aggregate structure. It is suitable for germination and growth of plants, and has improved strength and durability to the environment. The creation of a vegetation basement layer became possible.

A spray nozzle that can be used to practice the method of the present invention is shown in FIG. The muddy substrate (A) and the silicate compound (C) sent by the muddy substrate delivery pump reach the discharge port (1), and thereafter, the stirring cylinder (2)
It is gushing. Aggregating agent (B) and reaction modifier (D)
Is metered by the aggregating agent adjusting cock (3) and introduced into the stirring cylinder. The stirring cylinder is provided with a stirring blade (4) for promoting stirring. In order to further promote the mixing, it is preferable to introduce air by metering with an air control cock (6) through the air inlet (5).

As the silicate compound such as an alkali metal silicate compound and colloidal silica to be added to the muddy substrate used in the present invention, JIS standard water glass or colloidal silica is used alone or in combination. .

The reaction modifier promotes the gelation of the inorganic silicate compound. The reaction modifier is mixed and dissolved in the aggregate dissolution tank. Examples of the reaction modifier include bicarbonates such as sodium hydrogen carbonate and potassium hydrogen carbonate; chlorides such as magnesium chloride; sulfates such as magnesium sulfate and ammonium sulfate; bisulfates such as sodium hydrogen sulfate and potassium hydrogen sulfate; Phosphoric acid salts such as sodium hydrogen phosphate, potassium dihydrogen phosphate, sodium pyrophosphate and potassium pyrophosphate; inorganic reaction modifiers such as sulfuric acid, phosphoric acid and other mineral acids; organic acids such as acetic acid and citric acid; Organic reaction modifiers such as acetates, esters such as γ-butyrolactone, and dialdehydes such as glyoxal are used alone or in combination.

The following effects can be expected by mixing and using an inorganic silicate compound such as an alkali metal silicate or colloidal silica in a mud-like base material.

The aggregating agent, which is a polymer flocculant, and the mud-like base material are mixed at the spray nozzle or near the spray nozzle.
Agglomeration reaction occurs instantaneously, and a vegetation base layer having a high-order aggregate structure containing a high level of a clay component essential for plant growth is formed. Next, the alkali metal silicate compound and the inorganic silicate compound such as colloidal silica are gelled by the reaction modifier dissolved together with the aggregating agent, and a silicate gel almost containing the free water separated by the aggregating reaction is formed. Is done. As a result, the base material sprayed on the slope becomes more highly plastic and has high adhesion to the slope, greatly improving the workability and making it possible to work on steep slopes. Become.

Furthermore, since the hydrous silica gel structure (hereinafter abbreviated as hydrogel) can be formed at the initial stage of formation of the vegetation base layer immediately after construction, the vegetation base having excellent erosion resistance, particularly excellent frost heave resistance. Layer formation became possible.

In the conventional method of forming a greening base having a higher aggregated structure, the formed base layer holds a relatively large amount of water for a while after the application. At the time of construction and when the temperature after construction is higher than the freezing point of water (freezing point), excess water is separated and escaped from the formation base layer due to gravity, drying progresses, and shrinks slightly. The structure is more complete. On the other hand, in the case of a substrate exposed to a temperature below the freezing point after construction, there is a possibility that moisture that has not been completely separated freezes, and then, for example, the frozen moisture melts due to a rise in temperature during the day. In this way, immediately after construction, where the moisture contained in the base layer is relatively large, freezing, thawing,
That is, by repeating the expansion and contraction of the base layer, the completion of the higher-order aggregated structure was hindered, and in some cases, the higher-order aggregated structure was destroyed.

In the method of forming a greening substrate according to the present invention, the gap of the high-order aggregate structure is filled with the initial hydrogel to form the base layer, so that the freezing point can be lowered, and the water in the hydrogel is frozen. Even so, it was clarified that the water-impregnated gel can absorb the swelling pressure, so that the resistance of the formation base layer to freezing and frost heaving is greatly improved.

On the other hand, while the water in the water-impregnated gel is reduced by drying and the structure of the water-impregnated gel shrinks, it is gradually concentrated on the wall surface of the aggregated structure, and the abundant water, silicate compound, aluminum It is considered that a hydrated compound is formed by the compound and the calcium compound, and the hardness of the high-order aggregate structure is enhanced.

An alkali metal silicate for a muddy substrate;
The inorganic silicate compound such as colloidal silica is used in the range of 6.25 g / L to 125 g / L with respect to the muddy substrate. When the amount of the inorganic silicate compound such as alkali metal silicate and colloidal silica is 6.25 g / L or less, the amount of the hydrogel formed is not sufficient, and when spraying, a large amount of water separates from the formed base layer. There is a problem in workability on steep slopes and the like. On the other hand, when 125 g / L or more is used, the density of the silica gel formed in the formation base layer becomes high, plasticization proceeds excessively, fluidity is lost, and construction becomes difficult.

The reaction modifier which is dissolved and mixed together with the aggregating agent in the aggregating agent tank is within a range of 10% to 30% of the amount of the inorganic silicate compound such as alkali metal silicate, colloidal silica, etc. Is selected in consideration of the inclination and unevenness of the polymer to obtain an appropriate reaction rate. It is desirable that the reaction speed of the gelation be completed in several seconds to about 5 seconds.

In the case where the pH is shifted from neutrality due to the reaction modifier used, the pH can be adjusted by using aluminum sulfate or the like as an acidic component and calcium hydroxide or the like as an alkaline component.

The high-order aggregated structure thus formed retains the structure formed instantaneously by the aggregating agent and the mud-like base material, so that the water retention, fertilization, air permeability, and permeability are improved. It is highly water-soluble and retains the structure suitable for plant growth.

[0030]

[Example 1] An example of a construction test according to the present invention was carried out by the following method. (1) Formulation (i) Mud-like base material Soil (jet soil) 2500 L Curing / curing agent (jet seed) 180 kg Stabilizer (magzole D) 90 kg Alkali metal silicate 200 kg (JIS No. 3 sodium silicate) To 4000 L. (B) Agglomeration agent 600 g of an aggregation agent (soil floc) and 50 kg of a reaction modifier (MG Lock S manufactured by Mitsui Chemicals, Inc.) were dissolved in 400 L of clear water. C Seeds Herbaceous and woody seeds were added and mixed before spraying on muddy substrates.

(2) Spraying The material adjusted in (1) is installed at an inclination angle of 60 degrees.
70cm, width 80cm, depth 7cm box (test plate) 3cm thick
And 2 cm and twice. Seeds are 2cm thick in the latter half
At the time of spraying, the mixture was sprayed onto the muddy substrate. As a control, a base material was prepared and prepared in the same manner as in Example 1 except that the alkali metal silicate and the reaction modifier were not added in the formulation of Example 1. By mixing and spraying the test mud-like substrate with the aggregating agent in the nozzle, a vegetation base having a high-order agglomerated structure is instantaneously formed on the test plate, almost no separated water is generated, and the steep slope Despite the use of the test plate, it immediately adhered. When the formed vegetation base was observed over time, the hardness gradually increased. In addition, the pH of the formation base layer was 6.8, which was a value that was not a problem in plant growth. On the other hand, when the control section is constructed similarly,
Because of the large amount of separated water, the slightly formed base layer had a tendency to flow.

Specimens were prepared according to the following tests using the formulations of the examples, and the following examinations were made. 1. Rain resistance test A test specimen was prepared on the same test plate as in the example, and a raindrop having a diameter of 3 mm from a height of 5 m was dropped on a vegetation base on the test plate set at 45 degrees under the condition of a rainfall of 100 mm / Hr. And the amount of muddy components contained in the effluent was measured.

[0033]

[Table 1]

2. Compressive Strength A part of the base layer prepared in the examples was filled in a container having a diameter of 5 cm and a height of 9 cm, and the compressive strength after drying for 3 weeks was measured by using an Autograph AG-E type from Shimadzu Corporation.

[0035]

[Table 2]

3. Frost heaviness test A 1.5 L base layer was prepared using the formulation of the example and the control formulation, and was immediately transferred onto a sieve having a mesh size of 2 mm, and excess water was separated for 2 minutes. A 1 L glass beaker was filled with about 1 L of the making base layer. Then, it was placed in a thermostat that repeated a cycle of −3 ° C. for 6 hours and 10 ° C. for 6 hours, and the situation was observed.

[0037]

[Table 3]

[0038]

[Table 4]

In the example samples, a slight ice layer was formed on the surface layer, but even after 20 cycles, no breakage of the glass beaker due to freezing expansion occurred. On the other hand, in the control, the whole freeze gradually progressed with time, and three out of five cracks were formed in five cycles, and some of the beakers were broken off.

4. Submergence test A container having a length of 60 cm, a width of 30 cm, and a depth of 5 cm was sprayed on the container having a thickness of 5 cm according to the same formulation as in the example, and after standing for 5 weeks, a wave test was performed so that 30 cm in the vertical direction was submerged.

[0041]

[Table 5]

5. Germination growth test A specimen of 170 cm in length, 80 cm in width and 7 cm in depth was sprayed with 5 cm according to the formulation of Example 1. Installed at 45 degrees, 20
Five test plots of cm were prepared, and the following seeds were mixed in each test plot, mixed with a base layer having a surface layer of approximately 2 cm, and the germination rate and growth status were observed. One week later, watering was performed every morning except during rainfall.

[0043]

[Table 6] Germination rate measurement: Yamahanoki, Komatsunagi 28 days after Yamahagi, Medohagi 21 days after Italian ryegrass, weaving lovegrass 14 days after In addition, the growth status after germination was not different between the base of Example 1 and the control plot.

[Brief description of the drawings]

FIG. 1 shows a cross-sectional view of a spray nozzle that can be used in the method of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Discharge port 2 ... Stirring cylinder 3 ... Aggregating agent adjusting cock 4 ... Stirring blade 5 ... Air inlet 6 ... Air adjusting cock A ... Mud-like base material B ... Aggregating agent C ... Silicate compound D ... Reaction adjusting agent

Claims (1)

[Claims] 1. A muddy base material, which is a slurry obtained by mixing a vegetation base material containing clay and water, and a granulating agent, which is a polymer flocculant, are mixed at a spray nozzle or near a spray nozzle. In the method of forming a greening base having a high-order aggregate structure by spraying on the construction surface while causing an agglutination reaction, before mixing the mud base and the aggregating agent, the mud base is inorganic A method for forming a greening base, comprising: adding and mixing a silicate compound; and adding, to the aggregating agent, a reaction modifier for accelerating a gelation reaction of the inorganic silicate compound.