JPS642738B2 - - Google Patents

Description

[Detailed description of the invention]

[Technical Field of the Invention] The present invention relates to a material for a method of protecting a slope by covering it with a material, which is a method of stabilizing a slope. [Technical background of the invention and its problems] In recent years, as automobiles have become widespread, roads have been constructed in many places to accommodate this. Increasingly, roads are being constructed by cutting through. In this case, since the planned ground height is different from the conventional ground height, cutting is mainly required, and a cut slope will appear on the side of the road. If there is a risk of these slopes collapsing, vegetation construction methods, protection construction methods using artificial materials, stabilization construction methods using soil improvement, and mechanical stabilization construction methods using structures are applied. Vegetation construction methods and protection construction methods using artificial materials are widely used as relatively simple construction methods. The vegetation construction method uses the root systems of plants to stabilize the slope, but until the root systems of plants have developed, there is a high risk of washing away or collapsing due to rain, etc. , it must be suitable for growth, and it must itself have the effect of preventing washing away. Therefore, if the subsoil of the cut slope is exposed and the soil structure is unsuitable for plants, especially in the case of hard soil or bedrock, it is difficult for the root system to penetrate, and there is not enough fertilizer nutrients, so it is not easy to grow plants. Plant growth cannot be expected using the seed spraying method. For this reason, it is necessary to create a growth base on the slope that is suitable for plants and has the effect of preventing erosion. The essential requirements for the growth base are (1)
There are three requirements: (2) the topsoil does not move, (2) sufficient moisture is retained for germination, and (3) oxygen is appropriately supplied to the soil. Recently, one of the construction methods that satisfies these requirements is usually 5 to 15
A thick-layer soil spraying method with a soil thickness of about cm is often used, but this thick-layer soil spraying method has the disadvantage of being susceptible to erosion.In particular, if it rains immediately after construction, only the surface layer The entire sprayed layer often collapses due to the cut slope. One method to solve this drawback is to mix cement, binder, etc. into the spraying material. However, if a large amount of cement is mixed in, although it can be somewhat effective in preventing erosion, the strong alkalinity of cement inhibits the germination and growth of seeds, and the strong alkaline components are washed away by rain, causing the soil to deteriorate. Germination and growth may not occur until the temperature is close to neutral. Therefore, if there is heavy rain during this period, it is likely to be eroded. Even if there is no erosion, by the time the pH reaches a point where germination and growth are possible, the soil is often too hard and unsuitable for vegetation. Therefore, a neutralizing agent is mixed into cement to create an environment suitable for seed germination, but if enough neutralizing agent is added to completely neutralize the cement, Cohesion is reduced and erosion is more likely to occur. In this way, the method of mixing a neutralizing agent cannot be a fundamental solution. Another solution is to spray a material based on vegetable fibers. This method mainly uses short fiber peat moss and bark compost as vegetable fibers, and has considerable erosion prevention ability even immediately after spraying. However, this method has the disadvantage that since the sprayed growth substrate is mostly organic, there is a risk that it will gradually rot and disappear over a long period of time, and that the material cost is high. For this reason, attempts have been made to add some inorganic materials such as soil and sand, but when these materials are mixed, they tend to be eroded.
Since only a small amount can be mixed in, this cannot be a practical solution. Therefore, a method of incorporating a binder has been proposed, but it has been found that a considerable amount of binder must be used in order to improve the corrosion prevention effect, which is extremely economically disadvantageous. One way to improve this is to spray a binder onto the surface of the sprayed thick layer of soil instead of mixing in a binder, but the binder has no effect until it dries, and if there is rain before it dries, It will be eroded. Even after drying, if there is a long period of rainfall before plants germinate and grow and the slope is protected, the binder swells with water, gradually decreasing its adhesive strength and becoming eroded. Furthermore, when the surface dries, it becomes hard and becomes unsuitable for plant growth. By the way, in recent years, Japanese Patent Application Laid-open No. 55-68926,
Proposals have been made to mix nylon or glass fiber. It is certainly an effective proposal in that by mixing this type of non-natural fiber, the erosion prevention effect can be exerted even after the peat moss and bark compost have rotted and disappeared. However, this publication does not provide any teaching regarding the length, thickness, amount of fibers, etc. However, according to the findings of the present inventors, the shape and amount of fibers mixed are extremely important factors. If this point is not taken into account, there will be no effect on preventing erosion, and problems will arise in terms of mixing, etc. On the other hand, protection methods using artificial materials include plastic, soil cement method, net method, liquid synthetic resin spraying method, synthetic material, etc. Fiber cloth pine covering method,
Asphalt slope construction method (compaction method) There are asphalt panel construction methods, covering construction methods using synthetic polymer sheets, spraying construction methods, block construction methods, lattice frame construction methods, shelf construction methods, gabion cage construction methods, etc., but these methods are simple and reliable. The spraying method is the most widely used method. Generally, the spraying method is a construction method in which cement, mortar, and cement concrete are sprayed using compressed air pressure. The problem with the mortar spraying method is that it generally relies on compressed air to transport the spraying material, and the ratio of cement to aggregate is 1:4, compared to when it is used in general. Due to the poor blend, the compressive strength is low, and cracks are likely to occur, resulting in poor durability. For this reason, research has been conducted into incorporating steel fibers, alkali-resistant glass fibers, polypropylene fibers, etc. as reinforcing materials for mortar, and proposals have been made in JP-A No. 53-38105 and JP-A No. 55-65631, but there are issues with dispersibility and economy. Currently, it has not been put to practical use except for steel fibers. In addition, regarding the shape and amount of fibers other than steel fibers,
Previous proposals do not give detailed consideration, leading to problems in mixing, which is the key to dispersion. [Object of the Invention] The main object of the present invention is to solve the above-mentioned conventional problems and provide a slope protection material that can stably maintain slope surfaces and has excellent dispersibility. Other objects will be understood from the description below. [Summary of the Invention] The first invention to achieve this object is to use processed fibers having a shape of 5 to 50 mm in length, 3 to 50 denier in thickness, 10 or less crimps, and 20% or less of crimp rate. ~5wt%
It is characterized by the fact that it contains almost all of the remaining amount of earth and sand, and that it is mainly composed of these materials. The second invention has a shape with a length of 5 to 50 mm and a thickness of 3 to 50 mm.
Contains 0.05 to 5 wt% processed fibers with denier, 10 crimps or less, and 20% crimp rate, and 0.2 to 2 wt% cement, with almost all remaining earth and sand, and these constitute the main body. It is characterized by this. The third invention has a shape with a length of 5 to 50 mm and a thickness of 3 to 50 mm.
Contains 0.05 to 1 wt% of processed fibers with a denier of 10 crimps or less and a crimp rate of 20% or less, and 2 to 25 wt% of cement, with almost all remaining earth and sand, and these constitute the main body. It is characterized by this. As described above, the present invention is based on mixing processed fibers into earth and sand. Cement is also added if necessary. Processed fibers are natural fibers, chemical fibers, and synthetic fibers that have a constant shape, that is, those that have been processed to have a constant length, thickness, etc. Wood fibers, paper fibers, etc. are not processed. Since they are irregular in shape, they are not included in the processed fibers here. By mixing processed fibers into the earth and sand, it is possible to maintain stability over a long period of time, as well as to have a washout prevention effect, and by adding cement, even more stable slope protection can be achieved, and when mixed into mortar. has a high crack prevention effect and tensile strength. [Specific Examples of the Invention] The present invention will be explained in more detail below. Examples of fibers that can be used in the present invention include mineral fibers, glass fibers, mineral fibers, metal fibers,
Examples include peat moss, paper fibers, animal fibers, synthetic fibers, and chemical fibers. However, among these, mineral wool and glass fibers are easily broken when dispersed and kneaded in the spray mixture, and their entanglement is weak, so that their corrosion prevention effect is relatively small. Mineral fibers with uniform fiber length are difficult to obtain and are also expensive. Metal fibers have few such drawbacks, but the disadvantage is that they are weakly intertwined and easily corrode. Peat moss with a fiber length suitable for the present invention is difficult to obtain and expensive, and has the disadvantage of being corrosive. Paper fibers have the disadvantage of having low wet strength and being easily eroded. Animal fibers with a fiber length suitable for the present invention are expensive and have the disadvantage of being corrosive. Synthetic fibers and chemical fibers are easy to obtain with fiber lengths suitable for the present invention, and are relatively inexpensive. However, fibers such as nylon, vinylon, polypropylene, and polyethylene have poor weather resistance, and polyester is easily attacked by soil bacteria. Acrylic fibers do not have the above drawbacks and are the most preferred fibers for use in the present invention. However, it is not limited to acrylic fibers, but any fibers having similar shapes and properties can be used. If the fineness of the processed fiber used in the present invention is less than 3d (denier), there will be problems in terms of strength even if the fiber length is increased to strengthen the entanglement, and even if the number of crimps and crimp rate are decreased, the fiber length will not increase. If the length is long, the fibers will immediately become entangled with each other in the mixer to form a pill, which is undesirable. If the diameter exceeds 50d, it is too thick and the intertwining is weak, and it is also economically disadvantageous. Therefore, the fineness of the processed fiber is preferably 3 to 50 d.
Particularly preferred is 10-30d. Crimp is a very important factor to increase productivity.
20 to 25 crimps, like those normally used in spun yarn,
If the crimp rate is 30 to 40%, fluff will form during mixing and it cannot be used. (The number of crimps and the crimp rate are based on JIS: L1015 and L1016.) Therefore, the number of crimps is preferably 10 or less, particularly preferably 2 to 7. The crimp rate is 20% or less, particularly preferably 2 to 15%. During the manufacturing process, uncrimped fibers are bundled and passed through a cutter to produce fibers of a certain length.
Manufacturing is difficult from a practical and economical point of view because the dispersion significantly impedes productivity. To improve your productivity,
At least two crimps and a crimp rate of 2% are required.
Such crimping can be achieved by adjusting the spinning crimper. The length of the fibers used in the present invention is an important factor. That is, when the fiber length is less than 5 mm, the erosion prevention effect is relatively small, and a large amount of soil or earth and sand cannot be mixed into the sprayed/dispersed material. When using fibers having such crimps as described above, it is possible to disperse the fibers up to a fiber length of 50 mm. Fiber length is an important factor against erosion, and 5 mm has an erosion prevention effect against some rainfall, but 10 mm or more is required for heavy rain, and 20 mm or more is required for collected running water. A minimum of 30 mm is required to prevent surface erosion due to falling snow. The effect of incorporating fibers depends on the number of fibers present in the spray/dispersion material, so when using thick denier fibers, it is necessary to use a large amount in terms of weight. Therefore, the preferred fiber length is: Although it depends on the fineness, it is generally 5 to 50 mm, and 10 is particularly preferable.
~30mm. The amount of processed fiber mixed in is also important. There are three ways to mix this amount: when cement is not used (first invention), it is 0.05 to 6wt% because the processed fiber is expected to have an effect of preventing runoff, and when cement is used (second invention), this is 0.05 to 6wt%. Since it exerts the effect of preventing runoff together with processed fibers, it is considered to be in a relatively small amount of 0.05 to 2 wt%. If the mixing amount is small, the effect of preventing runoff will be low, and if the mixing amount is large, it will be uneconomical and the dispersibility in the material will be poor. When 2 to 25 wt% of cement is mixed (third invention), the effect of preventing washing away is mainly due to the cement, so the processed fiber is 0.05 to 1 wt%.
%, and the effects of processed fibers are mainly aimed at preventing cracks and improving tensile strength. Processed fibers also have a heat-insulating effect, making them effective in mitigating frost heaving in winter. Next, an example of a method for manufacturing the material of the present invention will be explained.
The first method is to premix a portion of the soil and sand that will be sprayed in the factory or near the site in advance to produce a premix material with a high fiber content, then transport it to the site and feed it into a mixer with the remaining soil and sand to form the predetermined material. It is stirred at a speed of . A high-speed concrete mortar mixer is preferred, in which shear stress is applied both horizontally and in the rotational direction of the stirrer in the mixer. On the other hand, a predetermined amount of fiber cut into a predetermined length is fed to the mixer at high speed through a focused tow through a guillotine-type fiber cutter installed above the mixer, and a predetermined amount of processed fiber is uniformly distributed in the earth and sand. 2 to 5 premix materials dispersed in
Produced in minutes. The second method is to produce premix materials in a factory on a large scale with high productivity. After spinning, the fibers are crimped to a specified length using a spinning crimper and cut into a specified length using a rotary cutter at high speed.The fibers are air-fed or sandwiched between belt conveyors and sent to a high-density packing room where they are compacted and packed under high pressure. and sent to the premix manufacturing plant. High-density packaging is dismantled within the premix manufacturing plant. If left as is, the edges may be hardened or entangled, and even if a predetermined amount is put into the mixer as it is and mixed, it will not be dispersed, so it is necessary to open the fibers. After examining various opening machines, we found that ``Fairnote'' has high productivity and evenly disperses fibers. By passing a predetermined amount of fiber mass through the "Fairnote" and immediately feeding it into the mixer using a directly connected blower and mixing, premix materials can be manufactured with extremely high productivity in a short time. The third method is to omit the premix material process, and is a method in which the entire amount of the sprayed material is put into the mixer at once on site, and after dry kneading, water is added. The first and second methods have the advantage that on-site processing is simple and quality can be easily stabilized. In the case of premix materials, the material manufactured in this way is mixed with the remaining soil on site, and in the case of on-site mixing, it is applied to the target bare ground using a sprayer or spreader with only the addition of water. Further, in the case of the second and third inventions, it is preferable to add cement at the site because cement is hygroscopic. In addition, the above-mentioned mixing mode is an illustration to the last, and is not necessarily limited. Further, in the present invention, no mention is made of the incorporation of an accelerating agent, a water reducing agent, a foaming agent, an antifreeze agent, a neutralizing agent, or a caking agent other than cement, but this does not limit the addition of these agents. In the first invention, the sediment mixed with processed fibers exhibits a wash-off prevention effect due to the entanglement of the fibers, and if seeds are mixed in, immediate greening can be expected, and even if seeds are not mixed, local plants will grow over time. Greening can be expected due to the flying of seeds. In the second and third inventions, it is suitable for steep slopes, rocky slopes, etc., where there is a concern about erosion, erosion, and collapse due to rain, and the effect is due to the prevention effect of fibers and the improvement of soil hardness due to the addition of cement. The effects work together to prevent runoff. If you expect plants to grow, the soil conditions for plant growth should be 23 mm or less (according to the Yamanaka soil hardness tester), as the plant's root system is well developed and the limit is 27 mm, so the cement should be kept at 2 wt% or less. The amount added must be controlled. The relationship between the amount of cement added and soil hardness is shown in Table 1.

[Table] It is said that a pH value of 5.5 to 7.5 in the substrate is optimal for plant growth, but as shown in Table 2, the increase in pH value due to the addition of cement decreases over time, and although it is slightly higher, the pH value increases after 20 days. Somehow, the pH value reaches a level where plants can grow.

【table】 Furthermore, the growth status of the plants is shown in Table 3.

[Table] If the purpose is simply to suppress the rise in PH value, it can be covered by adding a neutralizing agent, but as the amount of cement added increases, soil hardness increases and generally
As shown in the table, it has a negative effect on plant germination and growth.

〔Example〕

(Example 1) The washout prevention effect of the present invention will be shown by the results of an artificial rainfall test using soil using the processed fibers of the present invention and soil using no processed fibers (hereinafter referred to as blank). . In each experimental example, preparation of specimens and artificial rain tests were conducted as follows. Sand (river sand from Tone River, specific gravity: 2.60, FM: 1.90,
Maximum particle size: 2.5mm, unit weight: 1450Kg/ ^m3 , surface dry), processed fiber (product number: V-17B, Mitsubishi Rayon)
Acrylic fiber manufactured by Co., Ltd., fiber density: 15d, fiber length: 10
mm, no crimp) was mixed for 3 minutes using a mixer, and then water was added. The blended amounts of materials for each specimen are as shown in Table 5. The soil mixture created by the above method was
mm x length 500mm x height 50mm wooden box (volume: 10)
Stuffed into a push rod (iron, 7φ x 12cm, 2.6Kg)
After compacting the soil by hand using a soil compressor, the soil was left indoors for 3 days to obtain a test piece of soil according to the present invention. The blank was prepared in exactly the same manner as in the case of the specimen of the present invention described above, except that the processed fiber according to the present invention was not used. The blending amount of the blank specimen material is as shown in Table 5.

【table】

[Table] Each specimen created as described above was installed with an inclination of 45°, and the effective uniform distribution range of precipitation was approx.
A single nozzle is placed 1.75m from the surface of the specimen to obtain ^0.5m2 .
Precipitation was carried out at a rate of 150 mm/hr using a test device set at a height of . The amount of soil washed away is 5 minutes.
Measurements were taken every 10 or 15 minutes. The measurement results are shown in Table 6.

[Table] As is clear from the measurement results, within 10 minutes of rainfall, the soil runoff rate was 15% or less for specimens No. 3, 4, and 5 according to the present invention, and for blank and No. It was found that this material has high corrosion resistance compared to .2. In addition, blank specimen No. 1 collapsed after 1 minute and specimen No. 2 after 7 minutes, whereas no collapse was observed in specimens No. 4 and 5 according to the present invention, and specimen No. 3 collapsed after 7 minutes.
There was a slight outflow of soil. In addition, the results of a test using cement in conjunction with
Shown in the table. According to the same table, it can be seen that the addition of cement is extremely effective in increasing the washout prevention effect.

[Scope of application of the invention]

The scope of application of the present invention includes the creation of a growth base in slope greening work, the creation of a growth base in deserts and sand dunes, the creation of a growth base in strongly acidic soil, strongly alkaline soil, bedrock, etc. When used for slope greening work, it has an excellent effect of preventing runoff caused by rainfall and can form an effective growing base. When used for creating a growing base in deserts and sand dunes, it is effective against runoff caused by wind. It is also effective against erosion and can prevent sand from scattering. Furthermore, cuttings and planting can be carried out on the growth base formed in this way. Furthermore, even in the case of slope protection where greening is not expected, it is possible to increase the strength and provide excellent durability.

[Brief explanation of drawings]

The drawings show construction examples, and FIGS. 1 to 4 are cross-sectional views, and FIG. 5 is a plan view of the example shown in FIG. 4. 1... Nets, 3... Anchor pins, 4, 4A,
4B...Slope protection material, 5...Slope part.

Claims (1)

[Claims] 1. The shape has a length of 5 to 50 mm, a thickness of 3 to 50 denier,
Processed fibers with 10 crimps or less and crimp rate of 20% or less
Contains 0.05-6wt%, with almost the remaining amount being sediment,
A slope protection material characterized by comprising these as main components. 2 Shape: length 5-50mm, thickness 3-50 denier,
Processed fibers with 10 crimps or less and crimp rate of 20% or less
A slope protection material containing 0.05 to 2 wt% and 0.2 to 2 wt% of cement, with almost all remaining earth and sand, and which is mainly composed of these. 3 Shape: length 5-50mm, thickness 3-50 denier,
Processed fibers with 10 crimps or less and crimp rate of 20% or less
A slope protection material containing 0.05 to 1 wt% and 2 to 25 wt% of cement, with almost no remaining amount of earth and sand, and which is mainly composed of these.