JPH0157208B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a civil engineering material sheet for ground improvement using synthetic resin fibers. When constructing structures on flood control work, mountain control work, road construction, or reclaimed land, it is important to improve the ground in advance to prevent ground deformation and subsidence. Ground improvement works such as dispersing heavy stress, promoting compaction of soft ground, draining groundwater, protecting slopes, and filtering and separating earth and sand are usually carried out. Conventionally, when performing these construction works, civil engineering sheets made of various synthetic fibers have been used from the viewpoints of tensile strength, elasticity, water permeability, and durability. However, even these various synthetic fiber sheets are not sufficient as civil engineering sheets for ground improvement. For example, woven fabric sheets made of synthetic fibers have high tensile strength, but have low resistance to repeated loads, and do not have sufficient water permeability (drainage performance). On the other hand, although nonwoven fabric sheets have a high resistance to repeated loads and a high drainage effect, they have the problem of being easily stretched. Furthermore, laminated sheets made by bonding non-woven fabric sheets and woven fabric sheets with needle punching are also known, but these also have poor water permeability because the woven fabric sheets use synthetic fibers made of flat yarn, and also have poor water permeability due to the needle punch bonding. A drastic decrease in initial strength is observed. As a result of extensive research in view of the current situation, the present inventors have discovered a laminated civil engineering material sheet consisting of a nonwoven fabric sheet and a woven fabric sheet that has improved drainage performance and initial strength, and have completed the present invention. . That is, the present invention provides a nonwoven fabric layer formed by randomly arranging long fibers or short fibers of synthetic resin;
This is a civil engineering material sheet characterized by a textile fabric layer made of synthetic resin woven wool yarn, surface treated with a nonionic surfactant and bonded by needle punching. The nonwoven fabric layer formed by randomly arranging long fibers or short fibers of synthetic resin in the present invention is
Nonwoven fabrics made from long fibers (including continuous fibers) or short fibers such as polyamide fibers, polyester fibers, polyacrylonitrile fibers, polyvinyl alcohol fibers, polyvinyl chloride fibers, polyvinylidene chloride fibers, polyethylene fibers, polypropylene fibers, polystyrene fibers, etc. Either is fine as long as it is. Among these, nonwoven fabrics made of polyamide fibers, polyester fibers, polyvinyl alcohol fibers, polyethylene fibers, and polypropylene fibers are particularly preferred. The fibers may be molded with various draft ratios and draw ratios, but those with high strength and low elongation are particularly preferred. Furthermore, long fibers are preferable to short fibers due to the need for needle punching, which will be described later. The long fibers or short fibers of the nonwoven fabric layer are usually formed by melt spinning, and the randomized fiber groups are collected with a screen or the like to form a web. Furthermore, if desired, heat stabilizers, antioxidants, ultraviolet absorbers, pigments, flame retardants, surfactants, etc. may be added or surface treated during melt spinning, during web formation, before and after the web formation. .
The long fibers or short fibers of the nonwoven fabric layer produced in this way are 0.5 to 30 deniers, especially 3 to 30 deniers.
15 denier is preferred. The basis weight of the nonwoven fabric layer is 50 to 1000 g/ ^m2 , especially 100 to 500 g/m2.
^m2 is preferred. The synthetic resin ciliated yarn used in the textile fabric layer is a fibrillated yarn or ciliated yarn made of polyamide, polyester, polyacrylonitrile, polyvinyl alcohol, polyolefin, polystyrene, etc. Among these, polyethylene Polyolefin-based ciliary yarns such as polypropylene and polypropylene are preferred. Ciliated yarn is 300 to 2500 denier, especially
500 to 2000 denier is preferred. Furthermore, the fabric weight of the knitted fabric layer made of the above-mentioned ciliated yarn is 50 to 1000 g/
m ² , especially 100 to 500 g/m ² is preferred. Various stabilizers and pigments may be added to these synthetic resin ciliary threads, if desired. The ciliated yarn referred to here is a sublime type that does not have a network structure and has a spun yarn-like texture obtained by controlling the fiber distribution of each component fiber, and has a ciliated portion. It's about thread. The nonwoven fabric layer and the woven fabric layer can be bonded by overlapping the two layers and punching a needle through both layers. The structure of the laminate is preferably a two-layer structure of non-woven fabric layer/knitted fabric layer, or a three-layer structure of non-woven fabric layer/knitted fabric layer/non-woven fabric layer and knitted fabric layer/non-woven fabric layer/knitted woven fabric layer, but of course four or more layers are also possible. It is possible. The needle punch that penetrates both layers is per ^1cm2 .
30 to 150 times, especially 50 times or more, the bond between layers is good, the needle depth is 8 to 15 mm,
Particularly preferred is 10 to 12 mm. In the laminate thus obtained, since the textile fabric layer is made of ciliated yarn, the initial tensile strength decreases by needle punching is smaller than that of flat yarn, and the layer also has excellent water permeability.
Furthermore, by surface-treating both layers with a nonionic surfactant such as polyoxyethylene alkyl ether or polyoxyethylene alkyl phenyl ether before or during needle punching, the needle It is possible to further prevent a decrease in initial tensile strength by reducing fiber breakage in both layers due to punching, and both layers become hydrophilic, improving water permeability. The properties will be described in more detail. Figure 1 shows
Using a nonwoven fabric layer formed by randomly arranging long polypropylene fibers and a woven fabric layer made of polypropylene flat yarn, fibrillated yarn, and ciliated yarn,
The residual strength of the laminate when needle punching is performed 50 times per 1 ^cm2 while changing the needle depth (ratio of the tensile strength of the textile fabric layer of the laminate subjected to needle punching and the tensile strength of the original textile fabric) .Remaining strength = (Tensile strength of the textile fabric layer of the needle-punched laminate/
FIG. 2 is a diagram showing the relationship between the tensile strength of the raw textile fabric (x100) and the needle depth. Those made from ciliated yarns and fibrillated yarns have a smaller decrease in initial tensile strength even after needle punching than those made from flat yarns, and this effect is particularly remarkable in the case of ciliated yarns. Figure 2 shows two types of polypropylene long fiber nonwoven fabric and polypropylene ciliated yarn woven fabric, one that was needle-punched while surface-treated with a surfactant, and one that was needle-punched without surface treatment. It is a figure showing the relationship between tensile strength residual rate and needle depth. For those that have been surface-treated with a surfactant, the wetting of the fiber surface increases, the surface friction resistance decreases, and fiber breakage due to entanglement with the needle punch needle decreases, resulting in less decrease in tensile strength. I understand that. Table 2 shows the physical properties of the civil engineering material sheet of the present invention using knitted and woven fabrics made of polypropylene ciliated yarn, and the civil engineering material sheet using a woven fabric made of flat yarn in the woven fabric layer. It can be seen that the civil engineering material sheet of the present invention has higher water permeability and initial tensile strength than the civil engineering material sheet made of flat thread woven fabric. FIG. 3 is a diagram showing the relationship between tensile strength and elongation of the civil engineering material sheet of the present invention using a woven fabric of polypropylene ciliated yarn. In a tensile test, the civil engineering material sheet of the present invention shows that the strength rapidly increases after the start of tension until it reaches point A, and at point A, the threads of the woven fabric loosen or the fibers partially break. Then, the tensile strength decreases slightly and reaches point B. From point B, the tensile strength increases due to the intertwined fibers of the nonwoven fabric and reaches point C. At point C, the intertwined fibers of the nonwoven fabric are cut and the nonwoven fabric layer breaks. As described above, the civil engineering material sheet of the present invention has better initial tensile strength and water permeability (drainage performance) than conventional laminated civil engineering material sheets, and since the nonwoven fabric layer acts as a cushion material and protects the knitted fabric layer, Because it can provide tensile strength, elongation rate, and durability against repeated loads, and maintain its performance as a civil engineering material sheet over a long period of time, it can be used as a ground reinforcement material for stabilizing embankments and treating soft ground, and as a load-bearing material for roads, etc. Stress dispersion materials, consolidation accelerators for soft ground used in vertical drain construction methods, drainage materials for spring water, groundwater, etc., suction prevention materials and scour prevention materials used for river and sea revetments, and earth and sand separation materials. Mud prevention materials for railway road decks that require durability against loads, mortar or concrete spraying materials,
Used in a wide range of fields as civil engineering materials such as clogging prevention materials for underpass pipes, drainage materials and insulation materials for tunnels, oil spill prevention materials from pipelines, etc., asphalt-impregnated base materials used as water-stop sheets, waterproof sheets, etc. It can be used in Next, examples will be shown. Experimental example 1 Using a nonwoven fabric (fabric weight 200 g/cm ² , thickness 2 mm) made of polypropylene long fibers (8 denier), fibrillated polypropylene yarn (1500 denier), and ciliated yarn (1500 denier), each 1 inch The woven fabric is woven at intervals of 8 vertically and 8 horizontally, and the needle punches that penetrate both layers are used to increase the punch density.
The experiment was performed at 50 times/cm ² and at needle depths of 10, 12, and 14 mm. This laminated sheet was cut into strips of 5 cm x 20 cm, and the tensile strength and elongation were measured using an Instron tensile tester between 10 cm chucks at a tensile speed of 200 mm/min. The result is the first
Shown in the table.

【table】

[Table] Experimental Example 2 When manufacturing the laminated sheet of Experimental Example 1, a method was used in which needle punching was performed while spraying a nonionic surfactant at a rate of 4 g/m ² . Table 2 shows the performance of the resulting laminated sheet. Experimental Example 3 Using a non-woven fabric (fabric weight 200 g/m ² , thickness 2 mm) made of polypropylene long fibers (8 denier) and polypropylene flat yarn (1500 denier), weaving was carried out at an interval of 8 vertically and 8 horizontally per inch. A vine woven fabric was made and a laminated sheet was obtained in the same manner as in Experimental Example 2. The performance of the laminated sheet is shown in Table 2.

【table】

[Table] Experimental example 4 A nonwoven fabric (fabric weight 200 g/m ² , thickness 1.8 mm) made of polyethylene terephthalate (5 denier, fiber length 35 mm) and a polypropylene ciliary thread (1500 denier) were made of 8 vertically and 8 horizontally per inch. The woven fabrics woven at the book spacing were overlapped, and while spraying a nonionic surfactant at a rate of 4 g/m ² , needle punches were applied to penetrate both layers at a density of 50 times/cm ² and a needle depth of 10. , 12, and 14 mm, and laminated sheets were obtained. Table 3 shows the performance of the laminated sheet.

【table】

[Table] Experimental Example 5 A laminated sheet was obtained in the same manner as in Experimental Example 2 using a knitted fabric (fabric weight 120 g/m ² ) of polypropylene ciliated yarn (1500 denier) as the knitted fabric layer. Table 4 shows the performance of the laminated sheet. Experimental Example 6 A laminated sheet was obtained in the same manner as in Experimental Example 5 using a polypropylene flat (1500 denier) knitted fabric (basis weight 120 g/m ² ) for the knitted fabric layer. Table 4 shows the performance of the laminated sheet.

【table】

[Table] Experimental Example 7 A nonwoven fabric made of polypropylene long fibers (8 denier) (basis weight 200 g/m ² , thickness 2 mm) and polypropylene ciliated yarn (1500 denier) were woven vertically per inch.
A woven fabric woven at intervals of 16 strips and 16 strips horizontally was layered, and while spraying a nonionic surfactant at a rate of 4 g/m ² , a needle punch was applied to penetrate both layers at a needle punch density of 50 times/ Both layers were integrated under the conditions of cm ² and 90 times/cm ² and a needle depth of 12 mm. Table 5 shows the performance of this laminated sheet. Experimental Example 8 Experimental Example 7 A nonwoven fabric (fabric weight 100 g/m ² , thickness 1 mm) made of polypropylene long fibers (5 denier)
Both layers were stacked on both sides of the same woven fabric, and needle punched under the same conditions as in Experimental Example 7 to integrate both layers. Table 5 shows the performance of the laminated sheet. Experimental example 9 Polypropylene flat type (1600 denier)
A woven fabric layer woven at intervals of 15 vertically and 15 horizontally per inch was superimposed on the same nonwoven fabric as in Experimental Example 7, and a nonionic surfactant was sprayed at a rate of 4 g/m ² to penetrate both layers. Needle punch to needle depth 12
mm, and needle punch density was performed under conditions of 50 times/cm ² to integrate both layers. Table 5 shows the performance of this laminated sheet. Experimental Example 10 The same nonwoven fabric layer as in Experimental Example 8 was superimposed on both sides of the same woven fabric layer as in Comparative Example 3, and a three-layer laminate sheet was obtained under the same needle punching conditions as in Experimental Example 9. The performance of this sheet is shown in Table 5.

【table】

[Table] * In Comparative Examples 3 and 4, the nonwoven fabric layer also broke at the same time as the woven fabric broke.

[Brief explanation of drawings]

Figure 1 shows the residual strength of the woven fabric layer of a laminated sheet in which a polypropylene nonwoven fabric and a woven fabric layer plain woven using polypropylene ciliated yarn, defibrated yarn, and flat yarn are laminated and integrated by needle punching. It is a figure showing the relationship with the needle depth of a needle punch.
Figure 2 shows the relationship between the residual strength of the woven fabric layer and the needle depth of the needle punch when a polypropylene nonwoven fabric and a woven fabric of polypropylene ciliary yarn are integrated by needle punching, with and without surfactant. It is a diagram. FIG. 3 is a diagram showing the relationship between tensile strength and elongation of the civil engineering material sheet of the present invention.
FIG. 4 is an enlarged view showing one aspect of the structure of the ciliary thread used in the present invention.

Claims (1)

[Claims] 1 A nonwoven fabric layer formed by randomly arranging long or short synthetic resin fibers and a knitted fabric layer made of synthetic resin ciliary threads are surface-treated with a nonionic surfactant and bonded with a needle punch. A civil engineering material sheet that is characterized by: