JP2595322B2 - Railroad subbase - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a railway roadbed, and more particularly, to a railway roadbed with improved drainage.

[Related Art] If the roadbed soil supporting the railroad track structure has poor drainage properties and rainwater stays on the roadbed surface, the roadbed supporting the ballast is loosened with muddy water, and the ballast sinks into the ballast, possibly causing a railway accident. For this reason, a railway roadbed is known in which a nonwoven fabric mat alone or in combination with a waterproof sheet is laid under a ballast.

[Problems to be solved by the invention]

In the above-mentioned conventional railway roadbed, the moisture that has reached the waterproof sheet laid on the bottom of the ballast flows through the nonwoven fabric mat and is drained, but if the nonwoven fabric has low water permeability, the moisture in the roadbed is reduced. There is a risk of stagnation, weakening the roadbed and causing a railway accident.

In order to solve such a problem, a method of applying a surfactant to the mat to impart water permeability can be considered. However, surfactants and the like, which are generally widely used, flow out once rain has fallen, and have little effect in the second rain. This is clearly unsuitable for a mat which is virtually semi-permanently used in the subgrade.

The present invention has been made in view of such a point, and an object of the present invention is to provide a railway roadbed in which drainage of rainwater or the like is permanently high.

[Means for solving the problem]

The present invention has the following technical means in order to solve the above problems.

The railway roadbed according to the present invention focuses on the fact that when a mat formed of synthetic fibers is treated with a specific hydrophilic agent, the permanent water absorption of the fibers is markedly increased, and the sulfoion-dialkyl succinate is used. , An alkyl acid polyalkylene oxide, and a polysiloxane-polyalkylene oxide copolymer, a mat formed of synthetic fibers in which at least one surfactant selected from the group consisting of: Lay it down.

[Action]

Sulfonate-dialkyl succinate, polysiloxane / polyalkylene oxide copolymer, or polyalkylene oxide alkylate applied to a mat formed of synthetic fibers are all surfactants having high hydrophilicity, and the contacting ballast The water present in the voids is quickly drained and the ballast is dried quickly.

Each of the above surfactants has an extremely strong adsorbing power on synthetic fibers and is permanently fixed to the synthetic fibers.

 Hereinafter, the present invention will be described more specifically.

<Synthetic Fiber Mat> The synthetic fiber mat used for the railway roadbed according to the present invention is preferably a mat whose purpose is generally 400 g / m ² or more. The material for forming such a mat can be widely used as long as it is generally used for a synthetic fiber mat.

The synthetic fiber used as a raw material of the synthetic fiber mat in the railway roadbed according to the present invention may be a crystalline fiber or an amorphous fiber. Specifically, for example, low-density polyethylene, high-density polyethylene, polypropylene, poly 1-butene,
Polyolefin which is a homopolymer of olefin such as poly-4-methyl-1-pentene, or a random or block copolymer of α-olefins such as ethylene, propylene, 1-butene and 4-methyl-1-pentene. Certain polyolefins, ethylene / acrylic acid copolymers, ethylene / vinyl acetate copolymers, ethylene / vinyl alcohol copolymers, ethylene / vinyl compound copolymers such as ethylene / vinyl compound copolymers, polystyrene, acrylonitrile / styrene copolymers Polymers, acrylonitrile-butadiene-styrene copolymer, styrene-based compound copolymers such as methyl methacrylate-styrene copolymer, α-methylstyrene-styrene copolymer, polyvinyl chloride, polyvinylidene chloride, vinyl chloride Vinylidene chloride copolymer, poly Polyvinyl compounds such as methyl acrylate and polymethyl methacrylate; further, polyamides such as nylon 6, nylon 6-6, nylon 6-10, nylon 11, and nylon 12; thermoplastic polyesters such as polyethylene terephthalate and polybutylene terephthalate; Examples include polycarbonate and polyphenylene oxide. These synthetic fibers may be used alone or in combination with each other. Further, the synthetic resin as described above may be used by being mixed in a molten state before being formed into fibers.
When a polyolefin fiber is used in the present invention, it may be a polyolefin fiber containing a modified polyolefin graft-modified with an unsaturated carboxylic acid such as maleic acid or maleic anhydride, in whole or in part. .

In the present invention, among the above synthetic fibers, polyolefin, polyester, and polyamide fibers are particularly preferable. In particular, continuous filaments made of polypropylene are the most preferable because the fibers are not affected by bacteria in the soil and therefore are not easily corroded, and are stable against acidic soil and alkaline soil.

In order to produce a mat from the above synthetic fibers, various conventionally known methods used for producing a woven or nonwoven fabric can be used. In addition, as the mat used in the present invention, among the mats manufactured by such a method, a nonwoven fabric mat is particularly preferable because it has excellent drainage properties.

<Composition of Surfactant> Surfactants used by being fixed to a synthetic fiber mat on the railway roadbed according to the present invention can be broadly classified into three types of surfactants. That is, a sulfo ion-dialkyl succinate, an alkyl acid polyalkylene oxide, and a polysiloxane / polyalkylene oxide copolymer are exemplified. These may be used alone or in combination with each other. When used in combination, two or more surfactants may be fixed and used on one mat, and two or more surfactants may be fixed and layered on one mat. May be used.

The sulfoion-dialkyl succinate fixed on the synthetic fiber mat is an anionic surfactant and is represented by the following formula (1).

In the above formula (1), each of R ¹ and R ² is a linear or branched alkyl group having 4 to 20 carbon atoms. M ⁺ is a monovalent cation.

Specific examples of the cation represented by M ⁺ in the formula (1) include, for example, alkali metal ions such as Na ⁺ and K ⁺ , and NH ₄ ⁺
And the like. Of these, Na ⁺ is preferred.

The anionic surfactant represented by the formula (1), which is particularly preferably used in the railway roadbed of the present invention, includes sulfo sodium-di (2-ethylhexyl) succinate.

The alkylene polyalkylene oxide fixed to the mat together with the sulfoion-dialkyl succinate or alone is a nonionic surfactant and is represented by the following formula (2).

In the above formula (2), R ³ is an alkyl group having 10 to 20 carbon atoms. m is the number of repeating units in one molecule;
Is an integer. R ⁴ and R ⁵ are a hydrogen or a methyl group in which at least one of the parenthesized repeating units is always hydrogen. Note that R ⁴ and R ⁵ do not necessarily represent the same substituent among the respective repeating units arranged in a chain, and may be different regularly or irregularly.

The nonionic surfactants particularly preferably used in the railway roadbed of the present invention and represented by the above formula (2) include alkyl acid polyethylene oxide, alkyl acid polypropylene oxide, alkyl acid copoly (ethylene oxide / propylene oxide) and the like. Can be

A polysiloxane / polyalkylene oxide copolymer fixed to a mat alone or with a sulfoion-dialkyl succinate is a nonionic surfactant represented by the following formula (3).

In the above formula (3), R ⁶ is R ⁷ O (R ⁷ O) rR ⁷ OH. R ⁷ is an alkylene group having 1 to 10 carbon atoms, n and r are each an integer of 0 or 1 or more, and p and q are each an integer of 1 or more.
Note that n and p do not necessarily represent the same number among the parentheses {} that are continuous in a chain, and may be different regularly or irregularly. In particular, the nonionic surfactant used in the present invention and represented by the above formula (3) has an r of 10
Preferably, the surfactant is an integer of from 15 to 15. As the polyalkylene oxide represented by R ⁶ , polyethylene oxide, polypropylene oxide, and the like are preferable.

The fixing amount of these surfactants to the synthetic fiber mat may be appropriately changed depending on the type and basis weight of the mat and the required hydrophilicity level, but is usually 0.5 to 10 g / m ² , preferably In many cases, a range of 1 to 6 g / m ² is desirable. If it is less than 0.5 g / m ² , sufficient hydrophilicity may not be imparted to the mat. Also, the upper limit is not strict, but if it exceeds 10 g / m ² , the effect is not sufficient because the amount of the surfactant is large, so that it is not very advantageous.

<Fixing method of surfactant> The fixing method of the surfactant to the synthetic fiber mat is as follows.
Various known methods, for example, a spray method of spraying with a spray gun, a surfactant is placed on the uneven surface of the gravure plate with irregularities, the surfactant is scraped off with a spatula, and then the mat is placed on the gravure plate and pressed with a rubber roll. And a gravure coating method in which the surfactant in the concave portions on the uneven surface is transferred to the mat, a reverse coater method in which the surfactant is applied with a reverse coater, and the like. In the practice of the present invention, other fixing methods other than those described above will of course pose no problem as long as the adsorbing power of the surfactant to the fibers can be sufficiently ensured. The fixing of the surfactant may be performed before processing the synthetic fiber into a mat, or may be performed after processing the synthetic fiber into a mat.

The railway roadbed according to the present invention is formed by laying a mat formed of a synthetic fiber having a surfactant fixed thereon as described above under a ballast that supports a railway rail.

In order to lay the above-mentioned mat under the ballast which supports a rail for rails, usually, the mat is spread on the roadbed surface at the place where the rail line is laid, and the ballast is deposited on the mat. Subsequently, pillows are further laid on the upper surface of the accumulated ballast, and the track is fixed thereon to form a railway roadbed. The number of the above mats to be laid under the ballast may be one, but it is preferable that the water stop sheet is further laid on the mats so that "drainage" of the railway roadbed is further improved.

〔Example〕

 Hereinafter, embodiments of the present invention will be described with reference to the drawings.

<Example 1> A nonwoven fabric mat of the same size and a thickness of 0.4 cm manufactured by a spunbond method using polypropylene continuous filament as a raw material <Tafnel trade name (Mitsui Petrochemical Co., Ltd.)> Surfactant (sulfo sodium-
Dialkyl succinate) <trade name Sofran (Toho Chemical)
Hereinafter, an aqueous solution of “surfactant A”> (concentration: 10% by weight) was applied by a spray method. The amount of the aqueous solution applied to one of the nonwoven fabrics was 12 ml / m ² , and the amount of the aqueous solution applied to the other nonwoven fabric was 50 ml / m ² . They were then allowed to air dry and the surfactant settled on the nonwoven mat. Next, the nonwoven fabric mat 1 obtained by applying the aqueous solution in an amount of 12 ml / m ² in this manner is laid on a roadbed surface 2 having a transverse gradient of 3%, and a waterproof sheet 3 of the same size is placed thereon. Laying another nonwoven fabric mat 4 thereon, depositing a ballast 5 thereon, laying a pillow on the top, and then laying a rail 6 for railway on the top of the pillow, made.

A large amount of water was injected into the railway board obtained as described above with a hose. It was confirmed that the railway board was extremely drainable.

<Example 2> The same operation as in Example 1 was performed except that a polysiloxane / polyethylene oxide copolymer <hereinafter, referred to as "surfactant B"> was used as the surfactant.

As in Example 1, it was confirmed that "draining" was extremely good.

<Example 3> Alkyl acid polyalkylene oxide <
The same procedure as in Example 1 was carried out except that "Surfactant C" was used under the trade name Pronal (Toho Chemical).

As in Example 1, it was confirmed that "draining" was extremely good.

<Reference Example> A nonwoven fabric mat on which a surfactant was fixed was prepared in the same manner as in Examples 1 and 2, and the nonwoven fabric mat on which the surfactant was fixed was evaluated for hydrophilicity. The evaluation of hydrophilicity was performed by Test Method 1 described later.

<Test Method 1> Strip-shaped nonwoven fabric mat test specimen with surfactant fixed
About 2 cm of one end of 10 (6 cm × 2 cm × 0.4 cm) was immersed in water in a beaker placed on a weight scale.

When the nonwoven mat sucks water, the needle of the scale moves to a lower value. When the nonwoven mat repels water, the force for inserting the test piece into the water is applied, the apparent water increases in weight, and the needle of the scale moves to a large value. A change in the weight of water in the beaker 30 seconds after insertion was measured, and the water absorption of the test piece was calculated.

Subsequently, the test piece was dried again at 40 ° C. for another 24 hours, and the test piece was immersed in water in a beaker on a weighing scale in the same manner as described above, and the water absorption of the test piece was calculated. After the first immersion in this way, the drying and immersion treatment was repeated four times on the same test piece.

 The results are shown in FIG.

The vertical axis is the amount of water absorption. The negative value of the water absorption is the apparent water absorption that appears when the test piece repels water. The horizontal axis represents the number of times of immersion.

〔The invention's effect〕

According to the present invention, a specific surfactant is fixed to a mat formed of synthetic fibers. Since this mat is provided with permanent hydrophilicity, the railway roadbed according to the present invention enables efficient and permanent drainage of rainwater and the like.
Therefore, a large danger of moisture remaining in the roadbed and weakening the roadbed soil can be prevented for an extremely long time.

[Brief description of the drawings]

1 is a cross-sectional view of the railway ground according to the present invention, FIG. 2 is a cross-sectional view of a laminated sheet in which a waterproof sheet is laid between two mats on which a surfactant is fixed, and FIG. 3 is a test method. FIG. 3 is a graph showing the amount of water absorption by No. 1. 1,4 ... Mat with surfactant fixed 5 ... Ballast, 6 ... Rail rail

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Takashi Kato 61-2, Waki, Waki-cho, Kuga-gun, Yamaguchi Prefecture Inside Mitsui Petrochemical Industry Co., Ltd. (56) References JP-A-53-147306 (JP, A ) Actual opening 1977-66006 (JP, U)

Claims (2)

(57) [Claims] 1. A synthetic fiber formed by fixing at least one surfactant selected from the group consisting of sulfonate-dialkyl succinate, polyalkylene oxide alkylate, and polysiloxane / polyalkylene oxide copolymer. Railroad subbase with mats laid under ballasts that support railroad rails. 2. The railway roadbed according to claim 1, wherein a waterproof sheet is further laid on a mat formed of synthetic fibers having a surfactant fixed thereon.