JP7240706B2 - Agglomerated granulating active material and soil improvement method using the same - Google Patents

Description

The present invention relates to an agglomerated granulating activator that agglomerates and promotes granulation of soil with reduced drainage, particularly cohesive silt soil, and a method for improving soil using the same.

When the ground is used for a long period of time, the surface layer becomes viscous silt soil due to deterioration over time, and the drainage performance decreases. In such a case, a soil improvement method is adopted, such as carrying out the soil of the ground, mixing it with a soil improvement material and bringing it in, or replacing it with new soil.

However, carrying in and out of soil scatters dust in the neighborhood and causes noise and the like. Therefore, there is a demand for a method of improving soil while minimizing the carrying out and carrying in of soil.

The present invention provides agglomerating and granulating active material that agglomerates and promotes granulation of soil with reduced drainage such as cohesive silt soil, and a method for improving soil that minimizes carrying out and carrying in soil using the same. is.

The agglomerated granulated active material according to the present invention is
The powder is composed of magnesium oxide and calcium oxide in a total amount of 60% by mass or more, and the remainder being substantially water.

The powder is
40% by mass to 60% by mass of the magnesium oxide,
It is desirable to contain 15% by mass to 35% by mass of calcium oxide.

The powder preferably has a specific surface area (Blaine value) of 5000 to 7000 cm ² /g.

In addition, the soil improvement method of the present invention is
A step of spraying the above-mentioned agglomerate-granulated active material on the surface soil of the soil to be improved;
agitating the surface soil to mix the surface soil and the agglomerated granulated active material;
a step of rolling the soil containing the surface soil and the agglomerated active material;
and

Furthermore, the soil improvement method of the present invention is
excavating and sieving the topsoil of the soil to be improved;
A step of mixing the above-mentioned agglomerated granulated active material with the obtained surface soil;
returning the surface soil mixed with the agglomerated granulating active material to the soil and rolling it;
and

Since the agglomerated granulated active material according to the present invention is composed of powder containing magnesium oxide and calcium oxide as main components which are not harmful to soil, there is no problem in use. In addition, since these components are alkaline and not acidic, there is no risk of corroding metal parts such as a stirrer when mixed with soil.

The agglomerated granule-forming activator according to the present invention can coagulate and aggregate the viscous silt soil by spraying it on the soil and stirring it with the soil. As a result, soil covered with poorly drained clay soil can be improved into soil with excellent water permeability and good drainage. Furthermore, the agglomerated granulated active material according to the present invention removes class II specified hazardous substances such as lead, cadmium, mercury, arsenic selenium, boron, fluorine, and hexavalent chromium contained in soil by magnesium oxide and calcium oxide. They can be absorbed and insolubilized, and their elution can be suppressed, and detoxification of the soil can be achieved.

According to the soil improvement method of the present invention, the soil to be improved can be improved by spraying the above-described agglomerated activator on the soil and stirring and mixing with the soil. Therefore, it is possible to minimize the carrying out and carrying in of the soil, and also suppress the generation of dust and noise.

FIG. 1 is a sectional view of soil, where (a) shows the soil before improvement and (b) shows the soil after improvement. FIG. 2 shows an example of heavy machinery used in the soil improvement method of the present invention.

<Agglomerated granule activator>
The agglomerated granulated active material according to the present invention can be composed of a powder containing magnesium oxide and calcium oxide in a total amount of 60% by mass or more and the remainder being substantially water. Magnesium oxide and calcium oxide are alkaline materials, and by hydration reaction with moisture and inorganic components in the soil, the cohesive silt soil can be aggregated and granulated.

The powder preferably contains 40% to 60% by mass of magnesium oxide and 15% to 35% by mass of calcium oxide, and 45% to 55% by mass of magnesium oxide and 20% to 30% by mass of calcium oxide. % is more desirable.

The agglomerated granulated activator should be adjusted so that the specific surface area (Blaine value) of the powder is 5000 to 7000 cm ² /g. , and also suitable for spraying. More preferably, the powder has a specific surface area (Blaine value) of 6000 to 6500 cm ² /g.

FIG. 1 is a cross-sectional view before and after soil improvement. Soil can exemplify ground. FIG. 1(a) shows the soil before improvement. As shown in the figure, typical soil is composed of a base 10, a crushed stone layer 11, and a top layer of soil 12 layered on top. When the soil is used for a long period of time, the surface layer becomes viscous silt soil due to deterioration over time, and the drainage performance decreases. As shown in the figure, unevenness and mud are likely to occur on the surface.

First, the surface of such soil is leveled using a rake or roller. In addition, in order to improve the drainage capacity of the soil, as shown in FIG. It is desirable to fill the material 15 with high drainage.

Then, the above-described agglomerated granulated activator is spread over the surface of the topsoil 12 . It is preferable to spray about 2 to 4 kg of agglomerated active material per square meter. Of course, depending on the condition of the soil, the amount of agglomerated active material applied can be increased or decreased.

After the agglomerated and granulated active material is spread evenly over the surface soil 12, the surface soil 12 is dug up together with the agglomerated and granulated active material to stir and mix. It is preferable to excavate the topsoil 12 to a depth of about 50 mm to 150 mm. By mixing the agglomerating activator with the surface soil 12, the aggregating and granulating activator undergoes a hydration reaction with moisture and inorganic components to agglomerate the cohesive silt soil and the sandy silt soil to form aggregates. can be made Furthermore, the agglomerated granulated activator of the present invention has second-class specificity such as lead, cadmium, mercury, arsenic selenium, boron, fluorine, and hexavalent chromium contained in the surface soil 12 depending on the contained magnesium oxide and calcium oxide. It can absorb and insolubilize harmful substances, suppress their elution, and render the surface soil 12 harmless.

After stirring and mixing the aggregated and granulated activator with the topsoil 12, as shown in FIG. Just do it.

The surface soil 12 aggregated by the agglomerated granule activating material of the present invention is excellent in water permeability and drainage, so it can provide a well-drained ground. In addition, in the soil improvement method of the present invention, it is necessary to carry in the agglomerated active material, but since the carry-out and carry-in of the soil can be suppressed as much as possible, the generation of dust and noise can be suppressed, and the construction period can be reduced. can be shortened. Furthermore, since the second-class specified hazardous substances in the surface soil 12 can be insolubilized and rendered harmless, the ground can be used without anxiety after leveling.

In addition, as shown in FIG. 2, the soil improvement method of the present invention can work more effectively if it is a ground where a large heavy machine can be carried in. FIG. 2 shows part of the heavy equipment used for soil improvement work, which is an excavator 20, a crusher/sifter 30, and a mixer/reconstituter 40 in order from the left.

The pulverizer/sifter 30 has a function of pulverizing the surface soil 12 dug up by the excavator 20 and sieving it to a desired roughness. For example, the topsoil 12 is preferably sieved from 5 mm to 40 mm. The crushing/sieving machine 30 has a conveyor 31 and delivers the sifted surface soil 12 from the tip.

The mixing/returning machine 40 has a function of mixing the agglomerated granulated active material of the present invention and the surface soil 12 and returning the mixture to the soil. Specifically, the mixing/returning machine 40 has a packet 41 containing the agglomerated active material, and puts the agglomerated active material into the surface soil 12 delivered from the pulverizer/sieving machine 30 to form a spiral shape. The agglomerated and granulated active material and the surface soil 12 are mixed while passing through the mixing section 42 in which the screw is housed. The amount of the agglomerated activator to be put into the topsoil 12 can be adjusted by computer control, and the mixing ratio of the agglomerated activator can be freely set, for example, in increments of 1%. The surface soil 12 mixed with the agglomerated and granulated active material by the mixing unit 42 is delivered from the conveyor 43 provided at the tip of the mixer/returner 40 and returned to the soil.

In the soil improvement work using the excavator 20 , the crusher/sifter 30 and the mixer/returner 40 , the surface soil 12 is first excavated by the excavator 20 and put into the crusher/sifter 30 . The pulverizer/sifter 30 pulverizes and sieves the surface soil 12 to atomize the surface soil 12 to a desired particle size. Then, the surface soil 12 pulverized by the pulverizer/sifter 30 is sent from the conveyor 31 to the mixer/returner 40, and is mixed with the agglomerated granulated active material introduced from the packet 41 at a predetermined mixing ratio in the mixing unit 42. It is mixed and returned from the conveyor 43 to the soil. When the surface soil 12 is mixed with the agglomerating activator, the cohesive silt soil and the sandy silt soil are agglomerated and aggregated by hydration reaction with moisture and inorganic components. As shown in FIG. 1(b), the obtained surface soil 12 may be leveled using a rake, a bulldozer, a roller such as a wide tire roller, or the like.

According to the soil improvement method according to the present embodiment, the work from excavating the surface soil 12 to leveling the ground can be performed continuously, which is very efficient, suppresses the generation of dust and noise, and shortens the construction period. .

Since the improved soil has excellent water permeability and drainage, it can provide a well-drained ground.

The above description of the embodiments is for the purpose of explaining the present invention, and should not be construed as limiting the invention described in the claims or narrowing the scope. Further, each component of the present invention is not limited to the above-described embodiment, and of course various modifications are possible within the technical scope described in the claims.

12 Surface soil 20 Excavator 30 Crusher/sifter 40 Mixer/returner

Claims (3)

A powder containing 40% to 60% by mass of magnesium oxide, 15% to 35% by mass of calcium oxide, a total of 60% by mass or more of the magnesium oxide and the calcium oxide, and the balance being substantially water. consists of
The powder has a specific surface area (Blaine value) of 5000 to 7000 cm2/g,
An agglomerating active material that agglomerates and agglomerates viscous silt soil contained in the soil by spraying it on the soil of the ground and agitating it with the said soil. A soil improvement method comprising:
A step of spraying the agglomerated active material according to claim 1 on the surface soil of the soil to be improved;
agitating the surface soil to mix the surface soil and the agglomerated granulated active material;
a step of rolling the soil containing the surface soil and the agglomerated active material;
A soil amendment method comprising: A soil improvement method comprising:
excavating and sieving the topsoil of the soil to be improved;
mixing the obtained surface soil with the agglomerated granulated active material according to claim 1 ;
returning the surface soil mixed with the agglomerated granulating active material to the soil and rolling it;
A soil amendment method comprising:

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