JPH11107308A - Granulating method for sediment in lake and marsh formed by dam - Google Patents

Abstract

PROBLEM TO BE SOLVED: To granulate sediment efficiently and at a low cost by fractionating stone from sediment in lakes and marshes formed by dams to take the soil as starting material, controlling the moisture content of the starting material to a specified rate or less, mixing a binder and granulating the same. SOLUTION: Sediment drawn up from lakes and marshes formed by dams is subjected to fractionation to discharge stone material used in concrete aggregate by a grain size fractional machine. The fractionated soil as a starting material is dehydrated by a centrifugal separator to control the moisture content to 30% or less. Further, one or two kinds of binders among an inorganic binder composed of cement and/or plaster except clay minerals, an organic binder formed by a complex of acrylic acid, its derivative, polyvalent metal such as calcium or the like, and a binder composed of a water-soluble high polymer compound such as an acrylic acid-acrylic amide complex or the like are mixed with the soil, the moisture content of which is controlled, and granulated. Thus, the soil can be granulated efficiently at a low cost.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for granulating sedimentary soil in a dam lake.

[0002]

2. Description of the Related Art An enormous amount of sediment that flows in due to rainwater erosion or the like accumulates in dam lakes. In order to prevent a decrease in the water storage capacity of the dam, the bottom of the water is removed to remove sediment, but the amount is enormous. Among the sediment deposited in the dam lakes, sand and stone are effectively used as concrete aggregate.

[0003]

However, the sediment deposited in the dam lakes has a large amount of clay-rich soil, and only a small amount can be used as concrete aggregate.
The soil component containing a large amount of clay is easily densified and inferior in water permeability because of its fine particles, and also inferior in structural strength. For this reason, the soil component of the dam lake sedimentary soil cannot be used as agricultural or horticultural soil that requires water permeability, or as civil engineering soil that needs to be suitably compacted. Therefore, there is a problem that it is difficult to use sedimentary soil of dam lakes and marsh containing a large amount of clay for general purposes.

Accordingly, an object of the present invention is to provide a method of granulating dam lake sedimentary soil which can efficiently and inexpensively granulate the soil component of dam lake sediment so as to be suitably used for agriculture, horticulture or civil engineering. Is to provide.

[0005]

The present invention has the following arrangement to achieve the above object. That is, the present invention
The sediment used for concrete aggregate is separated from the dam lake sediment as a starting material, and the water content of the starting material is adjusted to 30% or less. One of systematic and organic binders
It is characterized in that granulation is performed by mixing seeds or two or more kinds.

Further, the starting material is a soil component containing a large amount of water immediately after being withdrawn from the dam lake, and the water content is adjusted by the dewatering means. Granulation can be performed efficiently without equipment.

The inorganic binder is cement and / or gypsum; the inorganic-organic composite binder is a composite of acrylic acid or a derivative thereof with a polyvalent metal; Since the system binder is a water-soluble polymer compound, the strength of the granulated soil can be suitably improved.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments according to the present invention will be described below in detail. The present invention is characterized by a method of granulating the starting material using the soil component after separating the stone material used for the concrete aggregate from the dam lake sediment as a starting material. That is, after adjusting the water content of the starting material to 30% or less, one or more of inorganic, inorganic-organic composite, and organic binders (cinders) excluding clay minerals are added. It is characterized by granulation by mixing.
According to this, an appropriate granulated soil can be obtained efficiently. For example, a suitable granulated soil in which the particle diameter of the granulated particles is 0.5 mm to 300 mm can be appropriately formed. The granulated soil can be suitably used for civil engineering, agriculture and horticulture. In addition, the above-mentioned water content is the ratio of the weight of water to the total weight of the starting materials, and in order to prevent the starting materials from flowing and to be able to handle them appropriately, a predetermined water content is required. It is necessary to make the content not more than the content.

Further, the starting material is a soil component containing a large amount of water immediately after being withdrawn from the dam lake, and the water content is adjusted by the dewatering means. Granulation can be performed efficiently without equipment. Centrifuge, press (press) as dehydration means
A machine and a heating and drying device may be used. If the water content is sequentially adjusted by using the dehydrating means, a consistent granulation process can be performed, continuous industrial production can be performed, and production efficiency can be improved.

[0010] Examples of the inorganic, inorganic-organic composite, and organic binders other than the clay mineral according to the present invention include the following examples. As the inorganic binder, cement and / or gypsum can be used. As the inorganic-organic composite binder, a composite of acrylic acid or a derivative thereof and a polyvalent metal can be used. Examples of polyvalent metals include calcium, magnesium, aluminum, and iron, which are used when strength is required for civil engineering applications. As the organic binder, a water-soluble polymer compound can be used.
Further, specific examples of the organic binder include an acrylic acid-acrylamide complex, those using polyvinyl alcohol and its silanol derivative alone or in combination, and emulsions of ethylene, phenol and vinyl acetate copolymer. . One or two of the above binders
Granulation using more than seeds can suitably improve the strength of the granulated soil.

Next, as examples of the binder, a case where an organic water-soluble polymer compound and an inorganic cement are used will be described in detail. First, a case where a water-soluble polymer compound as an organic binder is charged into the starting material obtained from a dam lake and granulated will be described. The sediment of the dam lake sediment contains a large amount of clay minerals. (Examples of clay minerals include montmorillonite, kaolinite, halloysite, and bentonite.) Therefore, when a water-soluble polymer compound is added to a starting material and mixed and kneaded, the water-soluble polymer compound and the starting material are mixed. The clay mineral originally contained reacts together and becomes a binder mainly composed of a complex of a water-soluble polymer compound and the clay mineral. The above-mentioned soil component can be suitably granulated by a binder containing this complex as a main component. The granulated soil thus generated is sufficiently strong as a backfill material after burying an underground buried object, and can be suitably used as a durable granular material such as water resistance.

The granulation system will be described. The dam lake marsh sediment lifted by a dredging ship or the like is first sent by a screw-type conveyor or the like, and the stones and the like used for concrete aggregates are separated by a particle size separator. It is separated and discharged. Then, the separated soil as a starting material is sent to a dewatering means, for example, a centrifuge, and after being dewatered to a predetermined moisture content, for example, to a drum type granulator rotating at a predetermined speed. Sent.
In this granulator, a predetermined amount of a water-soluble polymer compound is supplied to the fed starting material (including clay mineral) soil. In addition, a water-soluble polymer compound having an appropriately adjusted concentration may be supplied in the form of an aqueous solution in the form of an aqueous solution. The water-soluble polymer compound forms a composite with the clay mineral, and the composite functions as a binder. The amount of the complex added is 0.1% to 5.5% of the soil based on dry matter weight.
It is efficient, economical and good. The larger the surface area of the soil to be treated, the greater the proportion of addition. The granulated soil is dried mainly by hot air in the second half of the drum and discharged from the drum into the sieve. The screen consists of three stages with different eye sizes. Therefore, although roughly, it can be used in a predetermined place for each predetermined size range of the particle size, and can appropriately cope with use conditions.

[0013] By forming a binder by adding a cement-based additive to the composite, a granulated soil having higher strength and durability can be obtained. That is, granules produced by mixing a binder mainly composed of a complex of a water-soluble polymer compound, a clay mineral, and a cement-based additive with the soil component of the dam lake sedimentary soil, and granulating the mixture. Soil has strength and can be suitably used as a backfill material for civil engineering. In addition, as the granulated soil used for agriculture and horticulture, granulated soil generated using a binder mainly containing only a complex of a water-soluble polymer compound and a clay mineral is suitable. That is, it is considered better not to add a cement additive. This is because cement is alkaline and is considered to be a factor of growth impairment depending on the plant to be grown.

The operation and effect when a water-soluble polymer compound is used for aged general soil such as roads will be described below. Although there is a difference depending on the place, the deteriorated soil such as a road has a structurally single grain structure as referred to in pedology. In the single-grained soil, the proportion of the solid phase in the three-phase structure is large, and may account for 80% or more. In addition, the proportion of a phase that increases water permeability, such as a gas phase and a liquid phase, is small. On the other hand, the above-mentioned water-soluble polymer compound (for example, polyvinyl alcohol compound; polyvinyl alcohol and its silanol derivative, etc.) and one of clay minerals (for example, montmorillonite, kaolinite, halloysite, bentonite, etc.) Or two or more kinds of binders, which are mainly composed of a complex formed by reacting with each other, gather at the contact points of the single-grained soil particles, connect the soil particles, and have the aggregate structure referred to in pedology. It is particularly effective in making granulated particles. At this time, by using the polymer compound aqueous solution containing the complex, it is easy to control the particle size distribution of the granulated product, the physical strength of the formed granulated product can be increased, and the water resistance of the granulated product is high. . Moreover, since it becomes the granular material of an aggregate structure, water permeability is also high.

[0015] Accordingly, CB according to JIS A 1211 method used for evaluation of backfilling materials used in civil engineering work.
In the R test, the CBR value after water mixing can be made 3.0% or more, and the water permeability of the granulated soil layer is stably improved. Further, the three-phase component ratio of the granulated soil layer is also improved, and the ratio of the solid phase occupies around 60%. In order to obtain such improved physical properties, the total amount of the composite and the water-soluble polymer compound added to the soil to be improved is from 0.1 to 5.5 of the dry matter in terms of dry weight. By being in the range of% by weight, efficient granulation can be performed, and cost-effective granulated soil can be obtained. Of course, when the addition amount is further increased, both the water resistance and the physical strength are increased, but this is not practical in view of cost.

The operation and effect when the above-mentioned water-soluble polymer compound is used for dam lake sedimentary soil is basically the same as when it is used for aging general soil such as the roads described above. A granulated soil having strength and good water permeability can be obtained. As described above, the present invention has been described variously with reference to preferred embodiments. However, the present invention is not limited to the embodiments, and it is needless to say that many modifications can be made without departing from the spirit of the invention. That is.

[0017]

According to the method for granulating sediment of dam lakes and marshes according to the present invention, the water content of the starting material consisting of soil is reduced to 3%.
After adjusting to 0% or less, inorganic and inorganic except clay mineral
Granulation is performed by mixing one or more of an organic composite system and an organic binder. According to this, while the water contained in the dam lake sedimentary soil can be used effectively,
The clay minerals contained in the dam lake marsh can be effectively used, and no special water and clay minerals are required, and no special equipment is required for inputting and mixing moisture and inputting and mixing clay minerals. Therefore, according to the present invention, there is a significant effect that the soil component of the dam lake marsh sediment can be granulated efficiently and at low cost so that it can be suitably used for agriculture, horticulture or civil engineering.

Claims (5)

[Claims] 1. A soil material obtained by separating a stone material used as a concrete aggregate from a dam lake sediment is used as a starting material. After adjusting the water content of the starting material to 30% or less, an inorganic material excluding clay minerals is used. A method for granulating dam lake sedimentary soil, comprising granulating by mixing one or more of an inorganic-organic composite system and an organic binder. 2. The method according to claim 1, wherein the starting material is a soil component containing a large amount of water immediately after being withdrawn from the dam lake, and the water content is adjusted by a dewatering means.
The granulation method of the dam lake sediment described above. 3. The method according to claim 1, wherein the inorganic binder is cement and / or gypsum. 4. The dam lake sedimentary soil according to claim 1, wherein the inorganic-organic composite binder is a composite of acrylic acid or a derivative thereof and a polyvalent metal. Grain method. 5. The method of claim 1, 2, 3 or 4, wherein the organic binder is a water-soluble polymer compound.