KR100570412B1 - Geosynthetic clay liners - Google Patents

Abstract

The present invention relates to a geosynthetic clay ordering material, the ordering material has a configuration in which the bentonite layer is laminated on the upper surface of the nonwoven fabric bonded to the film on the bottom surface and the nonwoven fabric or woven fabric is laminated on the bentonite layer, the order of the laminated structure is inclined surface Even if installed in the main function, the loss of bentonite, which is the main function of order performance, is minimized, and the manufacturing cost is low.

Description

Geosynthetic clay liners {Geosynthetic clay liners}             

Figure 1 shows a schematic laminated structure of the geosynthetic clay water repellent material according to the present invention.

* Explanation of symbols for main parts of the drawings

1: film

2: lower nonwoven fabric

3: bentonite layer

4: upper woven or nonwoven

In the case of waste landfills and liquid reservoirs, geosynthetic clay water repellents, which are swelling soil waterproofing materials using bentonite materials having high hydrophilicity and swelling properties when contacted with moisture, are used to prevent leakage of liquids. The main component of bentonite, the swelling soil waterproofing material, is montmorillonite, a clay mineral that absorbs water when it comes in contact with water and causes a volume increase of 5 times its own weight and 14 to 16 times its dry weight. It exhibits a function to fill in cracks within mm.

Bentonite types include Na-bentonite, Ca-bentonite, sodium hydroxide bentonite, etc., and Na-bentonite, which has the largest swelling property, is mainly used for manufacturing geosynthetic clay water repellent materials.

Geosynthetic clay ordering means a composite material that is filled with bentonite between geotextiles or geomembranes and bonded by mechanical methods such as adhesive or needle-punching or stitch bonding.

These geotextile clay water repellent materials can be used in the environmental field (water repellent prevention, liquid storage or waste landfill, etc.), transportation field (contamination due to fuel loss in roads or railways), civil construction (dam, Leakage protection in tunnels, etc.).

When geosynthetic clay impregnated materials are used as waterproofing materials for such applications, it is particularly important to consider how waterproof the geosynthetic clay impregnated materials have. To this end, bentonite must have a definite waterproofness and, in the case of geotextile clay repellents using non-woven fabrics and woven mats, must be physically stable and maintain low water conduction.

However, the geosynthetic clay impregnated materials developed so far have problems that bentonite, which is waterproofing swelling soil, is lost through the gap between nonwoven fabric and woven fabric when applied to flat or sloped surfaces. Holding it. In particular, when installed on the inclined surface, the loss of bentonite becomes larger, and in severe cases, the bentonite is almost lost, leading to a situation in which it cannot properly function as a filler.

In addition, when installed on a flat surface without slope, the bentonite is lost due to the torn load during the installation of heavy equipment or truck, or partially submerged by rainwater after construction, thereby affecting the overall water quality. In particular, when applied to slopes, shear and pull-out characteristics are degraded due to friction with soil, and due to slope gradients, severe bentonite loss occurs under load, and in some cases bentonite is completely lost or bentonite is partially desorbed. It exists in a state and loses the function as a waterproofing material. In addition, when sutures of geosynthetic clay aberrations, the permeability coefficient changes due to the loss or thickness of bentonite in the seam and the expansion of the seam due to the swelling of the bentonite and the resulting decrease in strength.

In order to supplement these problems, the present inventors have developed a geotextile clay filler using a filler of a composite layer (see Korean Patent No. 10-284191). Although the geotextile clay repellent material has effectively solved the above problems, it has been pointed out that the manufacturing cost is high.

Therefore, to minimize the loss of bentonite in charge of the order performance, which is the main function of the geosynthetic clay clay of the present invention, and to provide a new geosynthetic clay clay to reduce the manufacturing cost compared to the existing product as a technical problem.

In the present inventor's research for solving the above problems, when a thin film is bonded to the bottom surface of the lower nonwoven fabric, it is possible to provide a geotextile clay water repellent material which can effectively prevent the outflow of bentonite on a flat or inclined surface at low cost. The present invention was made to know that it will be.

Therefore, according to the present invention, a bentonite layer is laminated on an upper surface of a nonwoven fabric to which a synthetic resin film is bonded to a bottom surface, and a geotextile clay repellent material is characterized in that a nonwoven fabric or a woven fabric is laminated on a bentonite layer.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

Figure 1 shows a laminated structure of geosynthetic clay water repellent material according to a preferred embodiment of the present invention. The illustrated geosynthetic clay clay has a structure in which a bentonite layer 3 is laminated on an upper surface of a nonwoven fabric 2 on which a film 1 is bonded, and a nonwoven fabric or woven fabric 4 is laminated on the bentonite layer 3. After lamination in this manner, needle punching and / or stitching can be performed.

The material of the synthetic resin film 1 bonded to the bottom surface of the lower nonwoven fabric 2 is preferably polyethylene, polypropylene, polyvinyl chloride, polyester, polyvinyl alcohol, or the like, and a hot melt method or thermal bonding is used for the bonding. desirable. Moreover, 3 mm or less is suitable for the thickness of a film.

The nonwoven fabric used in the lower portion is preferably a 10 to 15 denier polypropylene short fiber needle punching nonwoven fabric or a 5 to 10 denier polypropylene long fiber nonwoven fabric. In addition, as a polypropylene fiber which is a nonwoven fabric material, carbon black may be added in consideration of stability to ultraviolet rays when the exposure period is 30 days or more during or after construction. In particular, in the case of the polypropylene short fiber needle punching nonwoven fabric, the weight thereof is preferably 500 g / m 2 or less, and in the case of the polypropylene long fiber nonwoven fabric, the weight thereof is preferably 50 g / m 2 or less. If the fineness of the short fibers constituting the nonwoven fabric is greater than 10 denier, the fiber density per unit area increases, which leads to an increase in the cost of manufacturing the fiber, which makes it difficult to manufacture the fiber. If thicker than denier, the space between the fibers is increased, there is a disadvantage that the loss of bentonite between them during manufacturing, transportation, or construction.

As the bentonite layer 3, powdery bentonite or granular bentite may be used, and these may be used in combination. For example, the bentonite layer 3 may be formed by sequentially laminating a first bentonite layer containing granular bentonite and a water-soluble adhesive, and a second bentonite layer containing powdered bentonite and a water-soluble adhesive from the upper surface of the lower nonwoven fabric 2. have. In addition, a nonwoven fabric or a web may be inserted between the bentonite layers to improve the loss prevention and stability of the bentonite and to improve the tensile performance of the product. The bentonite interlayer laminate may be a nonwoven fabric having a weight of 50 g / m 2 or less (hereinafter referred to as an intermediate nonwoven fabric) of 5 to 10 denier polypropylene long fibers or a polypropylene web having a weight of 100 to 200 g / m 2. It is suitable.

In this order, the top layer consists of woven or nonwoven fabrics.

In the case of using the woven fabric for the upper layer, polypropylene or polyester woven fabric using 1,500 to 3,500 denier filament split yarn is preferable, and the weight of the woven fabric is preferably 500 g / m 2 or less for polypropylene woven fabric. In the case of polyester woven fabric, 50 g / m <2> or less is suitable. The reason why it is preferable to use filament split yarn as the material of woven fabric is that weaving is easier and tensile property is improved compared to that of ordinary yarn.If the fineness is thinner than 1500 denier, manufacturing cost increases and fibers There is a problem in that the loss of the bentonite is increased due to the increase in the spacing, and when the thickness is greater than 3500 denier, there is a problem in that the tensile property is reduced and the function is weakened.

And when using a nonwoven fabric in the upper layer, it is preferable to use a polypropylene short-fiber nonwoven fabric, the weight of the upper nonwoven fabric is preferably 500 g / ㎡ or less. The reason for using polypropylene as a material of nonwoven fabric is because of its excellent chemical stability. The resin may also be blended with carbon black in consideration of stability to ultraviolet rays. For example, it is preferable to mix | blend carbon black as much as possible in the case of the ultraviolet exposure period of 30 days or more during the construction of a surface nonwoven fabric or after construction. If the weight of this nonwoven fabric exceeds 500g / m2, it must be punched by using a thick needle, so that the damage of the product and the thickness of the nonwoven fabric are increased, so that the punching effect is lowered and the dimensional stability is insufficient. There is a disadvantage.

Features and other advantages of the present invention as described above will become more apparent from the following examples. However, the present invention is not limited to the following examples.

EXAMPLE

Laminated as shown in Table 1 to prepare a geosynthetic clay clay. The stacked elements used were:

Upper nonwoven fabric: A nonwoven fabric having a weight of 256.5 g / m 2 produced by needle punching short fibers of fineness 12 denier made of polypropylene containing carbon black.

First bentonite layer: Powdered bentonite incorporating a water-soluble adhesive.

Second bentonite layer: Granular bentonite incorporating a water-soluble adhesive.

Upper woven mat: Weaving with a weight of 138.3 g / m 2 with 250 denier filament split yarns.

Intermediate nonwoven fabric: Weight 32.4 g / m2 or 23.2 g / m2 nonwoven fabric produced by needle punching 8 denier polypropylene long fibers

Web: Polypropylene web weighing 146.8 g / m2

Lower nonwoven fabric-b: g / m 2 nonwoven fabric having a weight of 32.4 g / m 2 prepared by needle punching 8 denier polypropylene long fibers.

Lower nonwoven fabric-c: Polypropylene nonwoven fabric having a weight of 287.6 g / m 2

Film: Polyethylene Film

The geosynthetic clay repellent material of the above embodiment was examined and analyzed for physical properties of the following items, and the results are shown in Table 1 below.

Basic characteristics

 * Swelling degree of bentonite

 * Weight and thickness of geotextile clay

-Mechanical properties

* Tensile property: tensile strength and elongation in the longitudinal and width directions

* Bursting strength

* Longitudinal and widthwise fiber layer separation strength

* Tear property

* Friction property-Direct shear, drawing characteristics

-Hydraulic properties

Fluid loss

Moisture absorption

-Cold resistance: Judging from appearance change after 180 ° bend at minus 20 ℃ for 24 hours. ◎ indicates no change in appearance.

division Comparative example Example One 2 3 4 One 2 Swelling degree of bentonite (ml / 2g) 27.4 27.4 27.4 27.4 27.4 27.4  Weight (g / ㎡) Nonwoven Surface 256.5 256.5 256.5 256.5 256.5 Surface woven mat 138.3 First Bentonite Layer 1623.7 1623.7 1623.7 1623.7 1623.7 1623.7 Intermediate nonwoven 32.4 32.4 Web 146.8 Second Bentonite Layer 3788.6 3788.6 3788.6 3788.6 Lower nonwoven-b 32.4 Lower woven fabric 138.3 138.3 138.3 Lower nonwoven-c 287.6 287.6 287.6 film 56.2 56.2 Gross weight 5871.9 5953.9 5807.1 5988.8 2224 2105.8 Tensile Strength (㎏) Longitudinal direction 157.7 151.3 148.6 154.4 162.4 184.6 Width direction 96.4 92.7 88.2 98.5 113.7 135.2 Tensile Elongation (%) Longitudinal direction 98.5 104.6 105.3 100.2 94.4 86.6 Width direction 118.4 122.2 124.5 111.2 103.6 92.5 Bursting Strength (㎏) 58.3 54.4 53.6 60.3 68.3 73.5 Fiber layer separation strength (㎏) Longitudinal direction 21.4 19.8 17.6 23.7 28.2 32.4 Width direction 16.6 15.7 14.3 18.5 22.7 28.3 Fluid loss (ml) 14 16 18 15 8 6 Absorption rate (%) 584 603 645 822 878 893 Cold resistance ^* ◎ ◎ ◎ ◎ ◎ ◎

As described above, the geosynthetic clay ordering material using the lower nonwoven fabric in which the film is bonded to the bottom surface according to the present invention can minimize the loss of bentonite, which is the main function of ordering performance, even if installed on the inclined surface, There are advantages such as saving.

Claims (2)

In the geotextile clay water repellent material, a bentonite layer is laminated on an upper surface of a lower nonwoven fabric having a synthetic resin film bonded to a bottom surface, and an upper nonwoven fabric is laminated on a bentonite layer, and the lower nonwoven fabric is a needle having a polypropylene short fiber of 10 to 15 deniers. Punched nonwoven fabric or 5-10 denier polypropylene long fiber nonwoven fabric, The upper nonwoven fabric is a polypropylene short fiber nonwoven fabric containing carbon black, and the material of the film is polyethylene, polypropylene, polyvinyl chloride, polyester or poly Geosynthetic clay repellent material, characterized in that the vinyl alcohol. delete

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