JPS6117966B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a synthetic fiber nonwoven fabric for civil engineering drainage materials that is resistant to deformation in soil and has high water collection and drainage capabilities. How to dispose of underground water in civil engineering works is a very important issue, and various methods have been used to date, including natural materials such as sand, gravel, and crushed stone. , plastic pipes, nets, woven fabrics, non-woven fabrics, and other organic polymer materials, as well as combinations of natural materials and organic polymer materials, are in practical use.However, among these materials, natural materials are in short supply. As these materials are becoming increasingly difficult to obtain and require a lot of labor to construct, man-made organic polymer materials are increasingly being used. The typical drainage material used in the vertical drainage construction method, which is a typical drainage construction method, is a paper drain. Cardboard is used as a permeability device for this paper drain, but this essentially depends on the vertical hydraulic conductivity. Not only do they have the disadvantage of having a small vertical permeable area, but they are also weak in strength and deform in the soil, resulting in a decrease in drainage capacity.Furthermore, they are easier to construct than sand drains. However, paper drains have drawbacks such as being hard, difficult to bend, and difficult to handle. Furthermore, as an alternative to paper drains, products made from polyvinyl chloride plates with micropores, or products made by bending a plastic plate into a wave shape and pasting nonwoven fabric on the surface as a water-permeable device are in practical use. Also has the same drawbacks as paper drains. Another typical drainage method is the horizontal drainage method, and the drainage materials used in this method have traditionally been sand,
Natural materials such as gravel and crushed stone are often used, but also plastic pipes, mesh, textiles,
Organic polymeric materials such as nonwoven fabrics and combinations of the above-mentioned natural materials and organic polymeric materials are used. As mentioned above, natural materials are becoming difficult to obtain, and organic polymer materials are often used.
For example, a spring-like plastic bristle sandwiched between two sheets of non-woven fabric, or simply a thick non-woven fabric is used. However, like vertical drainage materials, these
It has drawbacks such as low hydraulic permeability coefficient in the horizontal plane, low hydraulic permeability area in the horizontal plane, and low mechanical strength. In view of the above-mentioned current situation, the present invention has a bending stiffness of 150.
Embossed synthetic fiber non-woven fabric with a diameter of at least By forming a large number of convex parts whose base length at the closest point is within the range of 1/3 to 3 times the height of the convex parts, the water collection area and drainage area are large, and the deformation in the soil is prevented. The purpose is to provide a nonwoven fabric for civil engineering drainage materials that is durable, has good workability, and is inexpensive.The present invention will be explained below based on the drawings. In FIG. 1, reference numeral 1 denotes a nonwoven fabric having a large number of convex portions formed by embossing, and is composed of a base portion 2, a rising portion 3, and a convex portion 4 consisting of a top portion. Embossed nonwoven fabric 1 like this
has a large number of convex parts, so the internal space 5 between the fabrics created by combining this embossed nonwoven fabric 1 with another flat sheet or combining a plurality of embossed nonwoven fabrics so that the convex parts are in contact with each other is utilized. It can collect and drain water, and its water permeability coefficient and water permeable area are extremely large compared to non-woven fabrics that are not embossed. In FIG. 2, an embodiment is shown in which the embossed nonwoven fabric 1 and the flat sheet 6 are combined. The water passes through the nonwoven fabric in the thickness direction at the rising portion 3 and is collected in the internal space 5 formed by the embossed fabric 1 and the flat sheet 6. At the time of water collection, the water only needs to penetrate the embossed nonwoven fabric 1 in the thickness direction, so the water permeability coefficient of the embossed nonwoven fabric 1 is extremely large, and moreover, the water permeability coefficient of the embossed nonwoven fabric 1 is extremely large, and moreover, Part 3
Since the embossed non-woven fabric 1 has a large water-permeable surface area, the embossed non-woven fabric 1 has a much larger water-collecting ability than a non-embossed non-woven fabric. Since the embossed nonwoven fabric 1 has convex portions only partially as shown in FIG. 1, the internal space 5 formed by the embossed nonwoven fabric 1 and the flat sheet 6 communicates over the entire surface. A drainage channel is formed, so that the water collected in the interior space 5 as described above is easily drained along the drainage channel. Inner space 5 like this
Since the water is connected throughout the area, its drainage capacity is extremely large. However, it is not sufficient to simply use embossed nonwoven fabrics as nonwoven fabrics for civil engineering drainage materials. That is, in order to obtain sufficient water collection and drainage effects as a nonwoven fabric for civil engineering drainage materials, it is necessary to increase the unevenness of the embossed nonwoven fabric 1, but when it is buried in the soil as a drainage material, The embossed nonwoven fabric 1 is subjected to pressure from the soil, and the base 2 and rising portion 3, which are the water collection surfaces, are crushed and lose their water collection and drainage abilities.The factors related to this crushing include the pressure from the soil. , the hardness of the embossed nonwoven fabric, the shape and number of embossments, etc. If the hardness of the embossed nonwoven fabric 1 is not sufficient, the internal space 5 will be crushed by the pressure of the soil.In order to avoid this, if the size of the unevenness of the embossed nonwoven fabric 1 is reduced, the internal space 5 will become smaller. At the same time, the drainage channels are crushed, and the water collection and drainage capacity becomes smaller. In order to increase the size of the unevenness of the embossed nonwoven fabric 1 and to prevent the internal space 5 from collapsing in the soil, it is necessary for the nonwoven fabric to have a certain level of rigidity, and as a result of various studies, JIS L-1079, 6.2.2. Bending Stiffness 6.22.5E method (handle-o-meter method, slot width 10 mm) It was found that a nonwoven fabric having a stiffness of 150 g or more was required. Next, the collapse of the unevenness of the embossed nonwoven fabric 1, which has an important relationship with water collection and drainage ability, also differs depending on the shape and number of embossing. If the length of the base of adjacent convex parts at the closest point is a, and the height of the convex part 4 is h, then the size of the water collection surface has a relationship with the sum of a and h, and the internal space 5 The area of is related to the product of a and h. If h is larger than a, the force in the direction of the large arrow B in Figure 2 will cause
Conversely, if h is smaller than a, the internal space 5 will be crushed by the force in the direction of the large arrow A. Furthermore, if a and h are both large, the structure is unstable against external forces and is likely to be crushed. Conversely, if a and h are both small, the area of the drainage channel becomes small, which is not preferable.
As a result of considering various factors regarding the dimensions of a and h, we found that 0.5mm<a<20mm, 0.5mm<h<20mm,
It has been found that if an emboss arrangement exists that satisfies h/3<a<3h, sufficient drainage capacity can be maintained against the pressure in the soil, and the water collection capacity is also excellent. The satisfying range of a and h is the third
Indicated by diagonal lines in the figure. In addition to the above, the embossed nonwoven fabric of the present invention is subjected to large stress during embossing due to the formation of deep embossments, and when used in soil, the volume of the soil changes due to drainage, and the soil Since the embossed nonwoven fabric is subjected to large deformation pressures due to positional movement, etc., the embossed nonwoven fabric must be able to sufficiently withstand these deformation stresses. If the strength and elongation of the nonwoven fabric is low, for example, in the case of a nonwoven fabric manufactured from short fibers by a wet method or a dry method, the nonwoven fabric may already be partially damaged during processing due to the large deformation stress of embossing. This results in the water being cut off, making it unable to function as a drainage material. Since synthetic fibers are used in the embossed nonwoven fabric of the present invention,
It has high strength and elongation, and even if large embossing is applied during processing or large deformation stress is applied during use, it will not cause partial breakage and can sufficiently withstand the deformation stress of soil. It is. When the embossed nonwoven fabric of the present invention is used as a drainage material for civil engineering, the embossed nonwoven fabric and a desired number of flat sheets such as films, nonwoven fabrics, and woven fabrics are superimposed, or two or more embossed nonwoven fabrics are stacked together as desired. Various types of composite materials can be used, such as stacking two or more sheets of embossed nonwoven fabric so that their protrusions are in contact with each other, or stacking two or more embossed nonwoven fabrics with a flat sheet in the middle so that their protrusions face each other. After forming the composite, the width is set to a desired length, and both ends are fixed by gluing, sewing, etc. along the length of the composite, and the composite is ready for use. As detailed above, the drainage material for civil engineering, which is made of rigid long-fiber nonwoven fabric with appropriate deep embossing, is inexpensive, easy to construct, has large water collection and drainage capacities, and has stable effects. It is a drainage material that has many advantages such as good drainage, can be applied in a variety of ways, and is useful as an excellent drainage material in all kinds of civil engineering works. The present invention will be explained below by giving examples. Example 1 Table 1 shows the composition and physical properties of a long fiber nonwoven fabric to be embossed.

[Table] The long fiber nonwoven fabrics shown in Table 1 were treated at 140°C with an embossing roll consisting of a metal roll and a paper roll having 5 mm x 5 mm square protrusions of 2 mm height at 2 mm intervals. The embossing depth of the embossed nonwoven fabric was 1.5 mm. Therefore, a and h of the embossed nonwoven fabric are a = 2 mm and h = 1.5 mm, respectively, so 0.5 mm < a (2 mm) < 20 mm, 0.5 mm < h (1.5 mm) < 20 mm, and h ( 1.5mm) < a (2mm) < 3h (1.5mm). One unembossed nonwoven fabric was sandwiched between the two embossed nonwoven fabrics described above, and the two outer fabrics were stacked one on top of the other so that the convex portions faced each other on the inside, and both ends of the nonwoven fabric in the length direction were sewn together. When the non-woven fabric drainage material made in this way was placed under embankment during consolidation of soft ground, the stabilization of the ground was significantly promoted. Example 2 Table 2 shows the composition and physical properties of the long fiber nonwoven fabric to be embossed.

[Table] Table 2 shows an embossing roll consisting of a metal roll and a paper roll having semi-spheroidal protrusions with a circular diameter of 7 mm and a peak height of 5 mm at intervals of 2 mm.
The long fiber nonwoven fabric shown in 1 was treated at 150°C. The embossing depth of the embossed nonwoven fabric was 4.5 mm. Therefore, a and h of the embossed nonwoven fabric are
a=2mm and h=4.5mm, respectively, so 0.5mm<a(2mm)<20mm 0.5mm<h(4.5mm)<20mm and h(4.5mm)/3<a(2mm)< 3h (4.5mm). One non-embossed nonwoven fabric is sandwiched between the two embossed nonwoven fabrics mentioned above, and the outer two fabrics are stacked so that the convex portions face each other, and 21 strips of hot melt adhesive are applied in the longitudinal direction of the nonwoven fabric. By partially adhering three pieces of nonwoven fabric to each other and cutting the bonded portion into pieces in the longitudinal direction, a long and narrow strip-shaped drainage material with a width of 10 cm was obtained. When the nonwoven fabric drainage material thus obtained was placed in the ground to stabilize soft ground and consolidation was performed using a normal method, consolidation was significantly accelerated.

[Brief explanation of the drawing]

Fig. 1 is a slope view of the nonwoven fabric for civil engineering drainage materials of the present invention, Fig. 2 is a sectional view of a composite of the nonwoven fabric for civil engineering drainage materials and a flat sheet, and Fig. 3 shows the satisfactory ranges of a and h. This is a graph showing. 1... Embossed nonwoven fabric, 2... Base, 3...
...Rising portion, 4... Convex portion, 5... Internal space, 6...
...Tabular sheet, 7...Soil.

Claims (1)

[Claims] 1 Embossed synthetic fiber nonwoven fabric with a bending stiffness of 150 g or more, so that the height of the convex portion and the length of the base at the closest point of the adjacent convex portions are each within the range of 0.5 to 20 mm, and The length of the base at the closest point of the convex part is 1/3 of the height of the convex part.
A nonwoven fabric for civil engineering drainage material formed with a large number of convex portions within the range of ~3 times.