JPH0135106B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a civil engineering material nonwoven fabric used as a sheet for a so-called block mat, in which a large number of concrete blocks, which are one type of civil engineering material, are attached to the sheet. The above-mentioned block mats are made by attaching a large number of concrete blocks to a sheet made of synthetic fibers, etc. that has a filtering property, and are considered to have excellent workability and resistance to soil surface erosion. It has come to be widely used in civil engineering materials such as However, the various performances required for civil engineering materials such as flood control and mountain control are extremely strict and special, so even if the block mat has excellent workability and erosion resistance, it is not necessarily satisfactory in terms of other performances. Nakatsuta. That is, since block mats are more advantageous in terms of construction, the more concrete blocks can be attached to one sheet, the more concrete blocks can be attached to one sheet. That is, for example, a sheet is usually 7m long x wide.
Make it a long object with an area of 2.1m and ^14.7m2
240 cubic blocks measuring 0.2m and 0.1m in height are installed. Each concrete block weighs approximately 5.6Kg.
Therefore, the total weight of the block is extremely large at 1344Kg. Therefore, the sheet must be able to withstand the weight of this heavy block, and since block mats are subject to rough handling and harsh work during construction, the strength required of the sheet is extremely high. However, in this respect, conventional block mats were still not sufficient. In this regard, for example, if the sheet is a woven fabric, it is necessary to increase the number of warp threads in order to increase the strength, but this makes it difficult to organize the warp threads, slowing down the weaving process, and increasing costs, making it impossible to make a material product. The result was that it was difficult to put it into practical use. In addition, there was also a problem with nonwoven fabric sheets regarding this strength. Another performance required of sheets is water permeability, but in the case of woven sheets, if you try to make them strong, the density of the fabric increases and good water permeability cannot be obtained, and even if you use non-woven sheets, needle punching When the throughput density was made finer, the strength increased to some extent, but the water permeability decreased. In any case, it has been difficult for conventional sheets to have both the strength and water permeability required for civil engineering materials. In view of the above-mentioned points, the present invention improves and eliminates the above problems, and uses a non-woven fabric that can solve the problems more advantageously than the above-mentioned woven sheet as a block mat sheet. The object of the present invention is to provide a nonwoven fabric for civil engineering materials that is extremely strong and has good water permeability. That is, the present invention uses polypropylene short fibers 1 and polyester long fibers 2 as constituent fibers of the nonwoven fabric for block mats in a weight ratio of 1/2 = 0.5 to 4.0, and the polyester long fibers 2 are in the form of thick threads of 3000 d or more. Arranged in the longitudinal direction, the strength in the longitudinal direction is 300Kg/5cm or more, and the permeability coefficient is 1×
Needle-punched to maintain a strength of 10 ^-1 cm/sec or more, this not only provides strength and water permeability within the desired range, but also allows for the adhesion of concrete blocks by the fluff on the surface of these short fibers. This makes it possible to do this easily and firmly. The configuration of the present invention will be explained in detail below with reference to some drawings. The present invention mainly uses polypropylene staple fibers because polypropylene fibers have a wide range of strength and elongation values, making them optimal as fibers for nonwoven fabrics, as well as being resistant to insects and mold, and resistant to soil acidity. This is because it is a highly durable and long-lasting fiber that has excellent resistance to alkalinity and alkalinity, and does not lose product performance over a long period of time, and is also economically advantageous. However, since these are short fibers, the fluff that forms on the surface of the nonwoven fabric can penetrate into the inside of the concrete block in its semi-solid state, making it easier to strengthen its function as an anchor than other synthetic fibers. By being. Also,
The reason why long-fiber polyester fibers are used is that this fiber has high strength per single fiber, and it is easy to make products with increased strength for use as materials. Furthermore, it is weather resistant as an aggregate and has strong alkali resistance against cement. The polypropylene short fibers 1 are mainly used, and the polyester long fibers 2 are arranged in the warp direction and mixed at a weight ratio of 0.5 to 4.0, and the water permeability coefficient is 1×10 ⁻
Needle punching is performed to maintain a pressure of cm/sec or more to form a nonwoven fabric a as shown in FIG. The nonwoven fabric a is made to have the same size as a conventional sheet. Note that the polyester long fibers 2 are used as thick yarns as shown in the figure. This nonwoven fabric a is used as a sheet, and a large number of concrete blocks 3 are fixed thereto by the anchoring action of the fluff 1' of the short fibers 1, as shown in FIGS. 2 and 3, to obtain a block mat b. Setting the weight ratio of polypropylene short fibers and polyester long fibers to 0.5 to 4.0 is the optimum method for easy industrial processing, judging from the number and strength of the polyester long fibers arranged in the warp direction. This is due to the fact that it is within a certain range. This 0.5 to 4.0
If it is outside the range, the strength will be significantly weakened and there will be no practical value at all, or on the contrary, the number of long fibers will be too large, causing problems in actual processing, or the water permeability will be significantly reduced. In addition, the reason why we limited the strength in the longitudinal direction to 300 kg/5 cm or more is that we need a strength of 300 kg/5 cm or more to withstand the weight of concrete blocks fixed on nonwoven fabric and moved, transported, and laid. This is because it was found to be absolutely necessary for construction purposes. If the strength is lower than this, the nonwoven fabric sheet may tear and there is a risk of accidents such as concrete blocks falling. This strength of 300 kg/5 cm or more can be achieved reliably by arranging polyester long fibers as thick threads in the warp direction and setting the weight ratio of polypropylene short fibers 1 to polyester long fibers 2 to 1/2 from 0.5 to 4.0. . Furthermore, in the present invention, the water permeability is set to 1×10 ^-1 cm/sec.
This is done to improve water permeability, improve the suction prevention effect, and prevent an increase in water pressure in ^the covered soil. It is possible to eliminate the possibility of troubles such as extrusion breakage of the surface. In addition, it is desired that the sheet has excellent adhesion to the cement of the concrete block structure, but in order to satisfy this adhesion, the needle punching conditions, especially the needle penetration density, must be adjusted according to water permeability, etc. It is important to decide based on the relationship between In other words, if the piercing density is too high, the fibers will become entangled and the water permeability will be reduced. Conversely, if the piercing density is too low, the short fibers and long fibers will not be integrated, which is not desirable as a product. This problem arises. Therefore, in order to have good water permeability, it is necessary to limit the piercing conditions within a certain range. In the present invention, needle punching is performed to provide a water permeability of 1×10 ^-1 cm/sec or more, which is necessary for exhibiting good water permeability. The above-mentioned piercing density for imparting water permeability is also effective for piercing the fluff of short polypropylene fibers into the concrete block and making the fluff act as an anchor to fix the block to the nonwoven fabric.
Strengthen the block's adhesion. Experiments have shown that having a high penetration density and a lot of fluff does not necessarily increase adhesive strength; rather, it is preferable to have less fluff and penetrate deeper into the cement. Based on the facts, the penetration density is determined taking into consideration the water permeability of 1 x 10 ^-1 cm/sec or more. In some cases, napping may be applied to obtain appropriate fluff density and length. The present invention will be further explained below with reference to Examples. Polypropylene short fibers 4d x 94mm, strength 4.1g/d, elongation
75% polyester long fiber, 1000d (4d×
250 strands), 1000 d made of 3 twisted yarns with a strength of 8 g/d
x3 = 3000 d of thread, and a nonwoven fabric was obtained using both as constituent fibers. In this case, the long fibers are supplied by installing a well-adjusted creel stand so that the tension is uniform, transferring them onto the lattice conveyor, stacking the short fiber web on top of the creel stand, and then stacking the short fiber web on top of it. Many were arranged and needle punched.
The conditions for needle punching are as follows: For the first needle, the needle penetration density is 100 needles/cm ² , the penetration depth is 18 mm, and the penetration direction is from above the web, and for the second needle, the penetration density is 70 needles/cm ² , and the penetration depth is 18 mm. depth
13mm, the piercing direction was from the bottom of the web. The following table shows the performance of a plurality of examples based on the above conditions.

【table】

[Table] As shown in the table above, the product of the present invention was significantly superior in strength to the conventional product, and also had appropriate water permeability. The block mats made of the nonwoven fabric sheets of each example were extremely firmly fixed by the fluff of the concrete blocks. As explained above, the present invention has a large number of concrete blocks fixed to one side of a rectangular unit sheet in a grid pattern, and is applied to the soil surface to prevent runoff and erosion caused by rainwater on the soil surface in fields such as mountain and flood control. A civil engineering material nonwoven fabric that is laid and fixed in the required number of sheets, with a weight ratio of 1 polypropylene short fiber and 2 polyester long fibers at a weight ratio of 1/2 = 0.5 to 4.0,
In addition, the polyester long fibers 2 are arranged in the warp direction in the form of thick threads of 3000 d or more to increase the strength in the warp direction.
300Kg/5cm or more, and the permeability coefficient is 1×
Since needle punching is performed to maintain the velocity at 10 ^-1 cm/sec or higher, the following effects are achieved. (a) Destination For example, when handling with a truck or crane when laying on residential slopes, river seashore seawalls, riverbeds, etc., the sheets are The long side is in the warp direction, and when the sheet is transported by holding both ends of the long side, it can sufficiently withstand the tension due to the weight of many concrete blocks fixed to one side of the sheet and prevent it from tearing. . (b) It is possible to cover and protect the soil surface for a long period of time by utilizing the inherent properties of the fibers that make up the sheet, such as strength and elongation, insect resistance, bacterial resistance, acid resistance, and alkali resistance. (c) Water permeability allows rainwater to penetrate into the installation surface, allowing plants to grow, and only water can be filtered through the installation surface and discharged to the outside, eliminating the need to bury drainage pipes. can be converted into

[Brief explanation of drawings]

The drawings show examples of the present invention, in which Fig. 1 is a perspective view of a fragment of the nonwoven fabric, Fig. 2 is a plan view of a part of a block mat using the nonwoven fabric as a sheet, and Fig. 3 shows the state in which the block is fixed. FIG. 1...Polypropylene short fiber, 2...Polyester long fiber, 3...Concrete block.

Claims (1)

[Claims] 1. A civil engineering material in which a large number of concrete blocks are fixed in a grid pattern to one side of a rectangular unit sheet, and the required number of concrete blocks are laid and fixed on the soil surface to prevent runoff and erosion caused by rainwater, etc. on the soil surface in fields such as mountain and flood control. It is a nonwoven fabric, and the weight ratio of polypropylene short fiber 1 and polyester long fiber 2 is 1/2 =
The ratio is 0.5 to 4.0, and the polyester long fibers 2 are arranged in the warp direction as thick threads of 3000 d or more, so that the strength in the warp direction is 300 Kg × 5 cm or more, and
A civil engineering material nonwoven fabric characterized by being needle-punched so as to maintain a water permeability coefficient of 1×10 ^-1 cm/sec or more.