Ridge painting method

Abstract

To provide a ridge coating method capable of satisfactorily maintaining a working environment by suppressing scattering of dust-like particles and forming a ridge having sufficient strength (uniaxial compressive strength) as a ridge by ridge coating.SOLUTION: A ridge coating method uses a ridge coating machine, as the ridge coating machine including tilling means for tilling a ridge before ridge coating to fill up the ridge to a ridge shape, and molding means for molding soil tilled by the tilling means to a ridge, and includes the following steps for: (a) forming a powder layer by spraying powder made of magnesium oxide-based solidified materials with a Blaine specific surface area being 2,000 cm2 / g or more on the surface of the ridge before ridge coating; (b) forming a granule layer by spraying grains including the grain size of 300 μm or more with a ratio of 80 mass% or more on the granule layer; and (c) tilling and molding the ridge before ridge coating undergoing the formation of the powder layer and the granule layer by using the ridge coating machine to form a ridge after ridge coating.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a ridge coating method. [Background technology]

[0002] In rice paddies, a process known as levee painting is known in which the banks of the paddy fields are repaired before the water is filled. This ridge painting is usually carried out by a tractor called a ridge painting machine. Known levee coating machines include a tilling means (pretreatment means) for tilling the levee before levee coating to build up a levee shape, and a shaping means (levee leveling means) for shaping the soil tilled by the tilling means (pretreatment means) into a levee. As an example, Patent Document 1 describes a ridge coating machine that is equipped with a pre-treatment body that is attached to the rear of a running body and receives power from the running body to till the original ridge and the field to build up a ridge-like shape, and a ridge leveling body that shapes the soil tilled by the pre-treatment body into a ridge, and that is provided with a side cover on the pre-treatment body to prevent soil from scattering, and that is characterized in that the side cover is supported by a parallel link so that it can move up and down freely, and the height of the side cover can be adjusted automatically.

[0003] As another example, Patent Document 2 describes a levee coating machine that includes a tilling unit supported by a machine body and having multiple tilling tines attached to a tilling shaft with a cantilever support structure for tilling and softening the slopes and edges of the levee, a levee coating drum unit in which a levee coating drum is attached integrally to a drum shaft located behind the tilling unit on the machine body, for coating the tilled and softened soil onto the slopes and upper surfaces of the levee, and a soil solidification material supply unit for adding soil solidification material stored in a tank via a hose to the soil that has been softened by the tilling tines of the tilling unit, wherein the tilling shaft has a length along a direction perpendicular to the longitudinal direction of the levee, and a screw conveyor is attached to a part of the tilling shaft close to the machine body for cutting up the soil at the edge of the levee and transporting it to the levee side, and the multiple tilling tines are attached to the free end side of the screw conveyor on the tilling shaft.

[0004] On the other hand, it is known to use a solidifying material made of lightly burned magnesium oxide powder in the construction of embankments. As an example, Patent Document 3 describes a ridge creation method that includes a soil sampling step of collecting soil samples from the ground from which soil to be used in creating the ridges is excavated, a solidification material determination step of mixing the soil sample with a solidification material (light-burned magnesium oxide powder) to be used to obtain a mixture, measuring the strength of the mixture after solidification, and determining the type and amount of solidification material to suppress the growth of weeds based on the obtained measured values, and a ridge creation step of creating a ridge in the ground using the type and amount of solidification material determined in the solidification material determination step. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 11-46508 [Patent Document 2] JP 2018-191527 A [Patent Document 3] JP 2019-176755 A Summary of the Invention [Problem to be solved by the invention]

[0006] The ridge coating machine described in Patent Document 1 has side covers to prevent soil from scattering. However, the side covers are thought to be less effective at preventing scattering of dust-like soil particles that fly up in the air than they are at preventing scattering of large soil particles that scatter in a specific direction. Patent Document 2 does not disclose any means for preventing soil from scattering, such as the side covers disclosed in Patent Document 1. On the other hand, the solidification material made of lightly burned magnesium oxide powder used for the construction of ridges described in Patent Document 3 has a Blaine specific surface area of ​​5,500 cm in the examples. 2 / g, which may cause problems such as soil being blown away during tilling. The object of the present invention is to provide a levee coating method using a levee coating machine, which can prevent dust-like particles from flying up during the levee coating work, thereby maintaining a good working environment, and can form a levee having sufficient strength (e.g., uniaxial compressive strength) for the levee by the levee coating. [Means for solving the problem]

[0007] As a result of intensive research into solving the above-mentioned problems, the inventors discovered that the above-mentioned object could be achieved by using a levee coating machine having a specific structure and adopting a levee coating method that combines the spreading of a specific powder, the spreading of a specific granular material, and tilling and shaping using the levee coating machine, and thus completed the present invention. The present invention provides the following [1] to [5].

[0008] [1] A method for applying ridge coating using a ridge coating machine, the ridge coating machine having a tilling means for tilling the ridge before applying ridge coating to form it into a ridge shape, and a shaping means for shaping the soil tilled by the tilling means into a ridge, the ridge coating method comprising: applying a magnesium-based solidification material having a Blaine specific surface area of ​​2,000 cm2 to the surface of the ridge before applying ridge coating; 2 1. A ridge coating method comprising the steps of: a powder coating step of coating a groundwater with a powder density of 300 μm or more and a powder layer of 100 μm or more to form a powder layer; a granular coating step of coating granular material containing 80% by mass or more of granular material having a particle size of 300 μm or more on the powder layer to form a granular layer; and a tilling and shaping step of using the ridge coating machine to till and shape the ridge before ridge coating on which the powder layer and the granular layer have been formed, to form a ridge after ridge coating. [2] The ridge coating method described in [1] above, wherein the granules spread in the granule spreading process are made of a magnesium-based solidification material (however, the magnesium-based solidification material constituting the granules may be the same as or different from the magnesium-based solidification material constituting the powder spread in the powder spreading process). [3] The method for applying ridge coating described in [2] above, wherein the magnesium-based solidifying material constituting the powder and the magnesium-based solidifying material constituting the granules are light-burned magnesia. [4] The ridge coating method according to any one of [1] to [3] above, wherein the amount of the powder is 20 to 80 parts by mass per 100 parts by mass of the total amount of the powder and the granules. [5] The amount of each of the powder and granules to be spread shall be such that the unconfined compressive strength of the part containing the powder and granules is 100 kN / m after 7 days, as measured in accordance with "JGS 0821-2009 (Test specimen preparation method without compaction of stabilized soil)" and "JIS A 1216:2020 (Unconfined compression test method for soil)". 2 The method for applying ridge coating according to any one of the above [1] to [4], wherein the above is satisfied. Effect of the Invention

[0009] According to the present invention, the scattering of dust-like particles (powder made of magnesium-based solidifying material) during ridge coating work can be suppressed, thereby making it possible to maintain a good working environment. Furthermore, according to the present invention, a ridge having sufficient strength (for example, uniaxial compressive strength) as a ridge can be formed by ridge coating. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The levee coating machine used in the levee coating method of the present invention has a tilling means for tilling the levee before levee coating to build it up into a levee shape, and a shaping means for shaping the soil tilled by the tilling means into a levee. The tilling means, which is a component of the ridge coating machine, has a tilling shaft that extends in a direction perpendicular to the traveling direction of the ridge coating machine (toward the side of the ridge coating machine) and a plurality of tilling tines (for example, 3 to 4 tines) fixed to the circumferential surface of the tilling shaft. The ridge, which has not been repaired since the ridge coating work about one year ago, is tilled by the plurality of tilling tines and raised into a ridge shape. The tilling claws can also be configured with an upper claw for tilling the upper surface, which is a horizontal plane, and a slope claw for tilling the side (slope), which is an inclined surface. In this case, the slope claw has a longer length than the upper claw.

[0011] The forming means, which is a component of the bank coating machine, has a cylindrical portion (part for forming the upper surface) for forming the upper surface of the bank, and a truncated cone-shaped portion formed by expanding the diameter from the end of the cylindrical portion, for forming the slope of the bank (part for forming the slope). The ridge coating machine corresponding to the ridge coating machine used in the present invention is commercially available from a number of manufacturers and is easily available. For example, a ridge coating machine manufactured by Kobashi Kogyo Co., Ltd., a ridge coating machine manufactured by Matsuyama Co., Ltd., a ridge coating machine manufactured by Kubota Corporation, etc. can be mentioned.

[0012] Next, each step constituting the ridge coating method of the present invention will be described. [Powder spreading process] The powder spraying process involves applying a magnesium-based solidifying material, Blaine, with a specific surface area of ​​2,000 cm, to the surface of the ridge before painting. 2 This is a process in which a powder having a density of 1 / g or more is spread to form a powder layer. Here, the above-mentioned "surface of the ridge before the ridge is painted" may be at least a part of the surface of the ridge. In the present invention, the "surface of the bank before the bank coating" is preferably the entire slope, more preferably the upper surface and the entire slope. By scattering the powder on such a preferable surface, the strength (uniaxial compressive strength) of the bank can be further increased. The magnesium-based solidifying material used in the present invention includes magnesium oxide and the like. Magnesium oxide (also called magnesia) is preferable because it does not make the soil strongly alkaline when added to the soil, and because it does not contain sulfur, there is no risk of hydrogen sulfide being generated. Among these, light-burned magnesia is particularly preferred because it has a large specific surface area and high reactivity. Light-burned magnesia is produced by firing a mineral whose main component is at least one of magnesium carbonate and magnesium hydroxide at 650 to 1,000°C.

[0013] The Blaine specific surface area of ​​the magnesium-based solidification material used in the powder spreading process is 2,000 cm 2 / g or more, preferably 3,000 to 10,000 cm 2 / g, more preferably 3,500 to 8,000 cm 2 / g, and more preferably 4,000 to 7,000 cm 2 / g, and particularly preferably 4,500 to 6,500 cm 2 / g. The specific surface area of ​​the blaine is 2,000 cm 2 / g or more, the strength (uniaxial compressive strength) of the ridge after ridge coating will be higher. 2 If the ratio is 0.1 to 0.1 g or less, the amount of dust particles scattered during ridge coating work will be reduced. The amount of powder to be sprayed is preferably 1 kg or more, more preferably 2 kg or more, and particularly preferably 3 kg or more per meter of the length of the ridge from the viewpoint of increasing the strength (uniaxial compressive strength) of the ridge after ridge coating. Although there is no particular reason to set an upper limit to the amount of powder to be sprayed, the ridge does not need to have excessive strength, and from the viewpoint of reducing the cost of materials, the amount is preferably 10 kg.

[0014] [Particle dispersion process] The granular scattering step is a step of scattering granular material containing granular material having a particle size of 300 μm or more at a rate of 80% by mass or more on the powder layer formed in the powder scattering step to form a granular layer. The particle size distribution of the granules used in the granular dispersion process preferably includes 80% by mass or more of particles having a particle size of 600 μm or more, and more preferably includes 80% by mass or more of particles having a particle size of 600 μm or more and 50% by mass or more of particles having a particle size of 850 μm or more. Furthermore, from the viewpoint of avoiding a decrease in the strength (uniaxial compressive strength) of the ridges after ridge coating, the particle size distribution of the particles preferably does not include particles having a particle size of 10 mm or more, or includes particles in a proportion of 20 mass% or less (preferably 10 mass% or less), more preferably does not include particles having a particle size of 8 mm or more, or includes particles in a proportion of 20 mass% or less (preferably 10 mass% or less), and particularly preferably does not include particles having a particle size of 6 mm or more, or includes particles in a proportion of 20 mass% or less (preferably 10 mass% or less).

[0015] The granules used in the granular scattering step include sand, ceramic granules, granules made of magnesium-based solidifying material, and the like. Among them, granules made of a magnesium-based solidifying material are preferred from the viewpoint of improving the strength of the ridge after ridge coating. For example, when using the same magnesium-based solidifying material as the powder used in the above-mentioned powder scattering step, first, a magnesium-based solidifying material in a lump form or the like may be crushed to obtain the granules used in the granule scattering step, and then a part of the crushed material may be further crushed to obtain the powder used in the powder scattering step. Alternatively, a molded product made of a magnesium-based solidifying material may be used as the granules used in the granule scattering step. The magnesium-based solidifying material used in the granular scattering step may be the same as the magnesium-based solidifying material used in the powder scattering step (e.g., light-burned magnesia) or may be different (e.g., heavy burnt magnesia, light burnt dolomite, etc.). Here, heavy burnt magnesia refers to magnesia produced in the same manner as light burnt magnesia, except that the firing temperature exceeds 1,000°C.

[0016] The amount of granules to be spread is preferably 1 kg or more, more preferably 2 kg or more, and particularly preferably 3 kg or more per meter of the length of the bank, from the viewpoint of further reducing the amount of dust-like particles scattered during the bank coating work. Although there is no particular reason for setting an upper limit to the amount of spread, if the amount of spread is too large, the effect of suppressing the amount of scattered dust-like particles becomes saturated, and from the viewpoint of the cost of materials, it is preferably 10 kg. The total amount of the powder to be spread in the powder spreading step and the granules to be spread in the granule spreading step is preferably 2 kg or more, more preferably 4 kg or more, and particularly preferably 6 kg or more per meter of the length of the bank. The upper limit of the total amount is not particularly limited, but is preferably 20 kg from the viewpoint of material costs, etc. The amount of the above powder out of a total of 100 parts by mass of the powder spread in the powder spreading process and the granules spread in the granule spreading process is preferably 20 to 80 parts by mass, more preferably 25 to 75 parts by mass, even more preferably 30 to 70 parts by mass, and particularly preferably 35 to 65 parts by mass, from the viewpoint of achieving a good balance between preventing the scattering of dust-like particles during the ridge coating work and improving the strength (uniaxial compressive strength) of the ridge after ridge coating.

[0017] The amount of each of the powder and the granules to be applied is preferably 100 kN / m as a value after 7 days of measuring the uniaxial compressive strength of the part containing the powder and the granules (in other words, the mixture of soil, the powder, and the granules formed by tilling and shaping) in accordance with "JGS 0821-2009 (Test specimen preparation method without compaction of stabilized soil)" and "JIS A 1216:2020 (Test method for uniaxial compression of soil)" with the time of tilling and shaping in the tilling and shaping step described later as the reference time. 2 More preferably, 150 kN / m 2 More preferably, 200 kN / m 2 More preferably, 250 kN / m 2 It is sufficient to determine it so that the above is satisfied. The uniaxial compressive strength can be measured using test specimens prepared by cutting a core from the ridge after plastering, or by taking a portion and shaping it. Although there is no particular reason to set an upper limit for the unconfined compressive strength, it is usually set at 400 kN / m2 since the ridge does not need to have excessive strength. 2 is

[0018] [Tillage and shaping process] The tilling and shaping process is a process in which the above-mentioned ridge coating machine is used to till and shape the ridge before ridge coating, on which a powder layer and a granular layer have been formed, to form the ridge after ridge coating. Here, "cultivation" refers to the cutting down of the levee before plastering and building up the levee shape using the plowing claws that constitute the plowing means of the levee plastering machine. "Molding" refers to the process of compressing the loose soil piled up in a levee shape by tilling to form a levee with a specific shape. Here, the specific shape of the levee is determined by the shapes of the two parts that make up the shaping means of the levee coating machine (the part for forming the upper surface and the part for forming the slope).

[0019] In the present invention, the effect of suppressing the flying (scattering) of dust-like particles is preferably as follows, as expressed in terms of the reduction rate of the amount of scattering measured by the test method in the examples described later. The reduction in the amount of scattered dust-like particles by using a combination of powder and granules (total amount: 100 parts by mass) is preferably 50% by mass or more, more preferably 60% by mass or more, even more preferably 70% by mass or more, and particularly preferably 80% by mass or more, compared to when only 100 parts by mass of powder is used. EXAMPLES

[0020] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. [Materials used] (1) Soil: Arakida soil (moisture content: 35%) (2) Powder: Light-burned magnesia powder (pulverized light-burned magnesia obtained by firing magnesite at 850°C; Blaine specific surface area: 5,500 cm 2 / g; "Powder" in Table 1) (3) Granule A: Light-burned magnesia granules (classified crushed material of light-burned magnesia obtained by firing magnesite at 850°C; having a particle size within the range of 850μm to 2.36mm in opening size; "Granule A" in Table 1) (4) Granules B: Light-burned magnesia granules (classified crushed material of light-burned magnesia obtained by firing magnesite at 850°C; having a grain size within the range of 2.36 mm to 4 mm in opening size; "Granules B" in Table 1)

[0021] [Example 1] The following tests were carried out using 7.5 parts by mass of powder, 2.5 parts by mass of "Granule A", and 90 parts by mass of soil. (A) Uniaxial compressive strength The specimen was prepared in accordance with "JGS 0821-2009 (Test specimen preparation method for stabilized soil without compaction)." In preparing this specimen, each material (7.5 parts by mass of powder, 2.5 parts by mass of "granular material A," and 90 parts by mass of soil) was put into a Hobart-type mixer and mixed for 10 minutes, and then sealed and cured for 7 days. After curing, the unconfined compressive strength of the specimens was measured in accordance with JIS A 1216:2020 (Unconfined compression test method for soil).

[0022] (B) Scattering rate of dust particles The ratio of the solidification material that had scattered (scattering ratio) to the total amount of the solidification material (powder and granules made of light-burned magnesia) was calculated by the following procedure. a) 0.36 liters of soil (90 parts by mass) was placed in a mixing bowl (volume: 1.3 liters). b) 7.5 parts by mass of powder was scattered over the entire top surface of the soil in the kneading pot to form a powder layer. c) Furthermore, 2.5 parts by mass of "Particle A" was scattered over the entire upper surface of the powder layer in the kneading bowl to form a particle layer. d) A paddle for uniformly mixing the contents of the mixing bowl (soil having powder and granular material A scattered thereon) was placed on the Hobart-type mixer body with the mixing bowl and the paddle in contact with each other, and the contents were then stirred for one minute. e) The mass of the solidification material that was blown up and scattered from the mixing bowl by the stirring in d) above was measured. The ratio (mass%) of the scattered solidification material to the total amount (10 parts by mass) of the solidification material contained in the mixing bowl in c) above was calculated, and the obtained value was taken as the "scattering ratio (mass%)".

[0023] [Examples 2 to 11, Comparative Examples 1 to 2] The test was carried out in the same manner as in Example 1, except that the materials shown in Table 1 were used. The above results are shown in Table 1. From Table 1, in Examples 1 to 11, the uniaxial compressive strength is 131 to 345 kN / m 2 The unconfined compressive strength of Comparative Example 2 (98 kN / m 2 ) it can be seen that the soil has gained strength that is capable of suppressing the growth of weed roots. Moreover, in Examples 1 to 11, the scattering rate of dust-like particles (solidifying material) was 0.01 to 0.85 mass%, which was significantly reduced compared to the scattering rate (1.40 mass%) in Comparative Example 1. The uniaxial compressive strength when light-burned magnesia powder is added is approximately proportional to the amount added. For example, in Example 5 or Example 10, where the amount of powder is 2.5 parts by mass, even if sand is used instead of Granule A (Example 5) or Granule B (Example 10), the amount of scattering of dust-like particles (magnesium-based solidification material) is reduced, and the specified uniaxial compressive strength (100 kN / m 2 or more) can be obtained.

[0024] [Table 1]

Claims

1. A method for applying ridge coating using a ridge coating machine, comprising: The ridge coating machine has a tilling means for tilling the ridge before ridge coating to build up the ridge shape, and a shaping means for shaping the soil tilled by the tilling means into a ridge, The above-mentioned ridge painting method is The surface of the ridge before the ridge coating is made of light-burned magnesia with a Blaine specific surface area of ​​2,000 cm ２ A powder spraying step of spraying a powder having a particle size of 1 / g or more to form a powder layer; A granular scattering step of scattering granular particles made of light-burned magnesia containing particles having a particle size of 300 μm or more in a ratio of 80% by mass or more on the powder layer to form a granular layer; A tilling and shaping process in which the ridge before ridge coating, on which the powder layer and the granular layer are formed, is performed using the ridge coating machine to form a ridge after ridge coating; A method for coating a ridge, comprising:

2. 2. The ridge coating method according to claim 1, wherein the amount of said powder is 20 to 80 parts by mass per 100 parts by mass of the total amount of said powder and said granules.

3. The amount of each of the powder and the granules to be spread is set so that the uniaxial compressive strength of the part containing the powder and the granules is 100 kN / m after 7 days, as measured in accordance with "JGS 0821-2009 (Method for preparing specimens without compaction of stabilized soil)" and "JIS A 1216:2020 (Method for testing uniaxial compression of soil)". ２ The method for ridge painting according to claim 1 or 2, wherein the above-mentioned conditions are met.

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