Composite geotextile and slope protection method based on composite geotextile

Abstract

The application discloses a kind of composite geotextile and the slope protection method based on composite geotextile, comprising: jute fiber is treated by bio-enzyme method and hydrothermal method in sequence to obtain modified jute fiber;With modified jute fiber as base layer, sugarcane fiber is laid on base layer as middle layer, and then modified jute fiber is laid on sugarcane fiber as surface layer, and composite geotextile is obtained by weaving;Composite geotextile is laid on slope, base layer is oriented to slope soil, and horse hoof gold seeds are sown on surface layer.The slope protection method uses composite geotextile for slope reinforcement in early stage;With the extension of time, sugarcane fiber is gradually degraded, and in the degradation process, it can enhance the strength of soil body while promoting the growth of horse hoof gold, and after growth is completed, horse hoof gold and modified jute fiber are mainly used for slope reinforcement in later period, so that the slope protection method can play a good slope protection effect in the whole process.

Description

Technical Field

[0001] This invention relates to the field of geotechnical engineering technology, and in particular to a composite geotextile and a slope protection method based on the composite geotextile. Background Technology

[0002] Slopes are an important component of highways and waterways. Improper handling can easily lead to breakage, collapse, landslides, or even mudslides, which not only damage the environment but also affect the normal operation of highways and waterways. In severe cases, they can also cause traffic disruptions, affect the normal flood discharge of waterways, and cause significant economic losses.

[0003] Most slope damage is caused by the infiltration of rainwater into the slope surface during heavy rain, which increases pore water pressure and reduces slope stability, leading to slope failure. Traditional slope reinforcement methods use grouting and reinforcement to form a concrete layer on the slope surface for protection. Although this method can maintain slope stability, it has the following problems: (1) When spraying concrete, due to the high rebound rate of concrete, it cannot fully bond the concrete to the slope surface, resulting in a large waste of concrete; (2) Rainwater erosion, temperature changes, and construction operations can easily cause cracks in the concrete layer, which makes it easy for water to seep into the soil; (3) Traditional reinforcement methods have a long construction period.

[0004] In addition, vegetation is currently used for slope protection. However, in the early stages of plant growth, it is often difficult to produce good slope protection results.

[0005] In view of this, it is necessary to design a composite geotextile and a slope protection method based on the composite geotextile to solve the above problems. Summary of the Invention

[0006] The purpose of this invention is to provide a composite geotextile made of modified jute fiber and sugarcane fiber, combined with the vegetation protection effect of Dichondra repens, for protecting non-cohesive soil slopes, and a slope protection method based on the composite geotextile.

[0007] To achieve the above-mentioned objective, this invention provides a method for preparing a composite geotextile, comprising the following steps:

[0008] S1. Modified jute fiber was obtained by sequentially treating jute fiber with a bio-enzymatic method and a hydrothermal method.

[0009] S2. Using the modified jute fiber obtained in step S1 as the base layer, sugarcane fiber is laid on the base layer as the intermediate layer, and then the modified jute fiber is laid on the sugarcane fiber as the surface layer, and a composite geotextile with a three-layer composite structure of modified jute fiber-sugarcane fiber-modified jute fiber is woven.

[0010] As a further improvement of the present invention, in step S1, the bio-enzymatic operation is as follows: jute fibers are placed in laccase at a pH of 5-6 and a concentration of 1-2%, and enzymatically hydrolyzed at 60-70°C for 1.5-2.5 hours, wherein the mass ratio of jute fibers to laccase is 1:18-1:22. After bio-enzymatic treatment, the proportion of lignin and hemicellulose in jute fibers can be reduced, increasing the moisture regain and softness of the jute fibers. Furthermore, compared with traditional alkali treatment, bio-enzymatic treatment is more economical and does not cause fiber damage. After bio-enzymatic treatment, the surface morphology of the jute fibers remains almost unchanged, facilitating subsequent hydrothermal treatment.

[0011] Because the hydroxyl content in jute fiber increases after laccase treatment, the ability of jute fiber to adsorb soil microorganisms decreases. Therefore, further modification treatment of jute fiber is required by hydrothermal method.

[0012] As a further improvement of the present invention, in step S1, the hydrothermal method is as follows: the jute fibers treated by bio-enzyme are washed with ethanol and water and then dried, then soaked in boiling water for 1.5-3.5 hours, and then rinsed with deionized water to remove the chemical substances on the fiber surface. After drying, modified jute fibers are obtained. The modified jute fibers have improved toughness and can induce calcium carbonate precipitation in conjunction with soil microorganisms to improve the soil's infiltration capacity, thereby achieving the purpose of reinforcing slopes. At the same time, the precipitation of calcium carbonate can also solve the problems of damage and aging of composite geotextiles that affect their seepage prevention capacity. Compared with traditional geomembranes that are prone to tearing, puncture, and aging, composite geotextiles are more suitable for long-term enhancement of the seepage prevention capacity of non-cohesive soils.

[0013] As a further improvement of the present invention, the drying temperature is 60-80℃.

[0014] As a further improvement of the present invention, in step S2, the textile process is a needle-punching process. Compared with traditional woven geotextiles, needle-punched geotextiles are more conducive to plant growth.

[0015] As a further improvement of the present invention, in step S2, the thickness ratio of the base layer, intermediate layer and surface layer is 1:3-5:1.

[0016] As a further improvement of the present invention, in step S2, the unit area mass of the composite geotextile is 750-950 g / m². 2 .

[0017] The present invention also provides a composite geotextile, which is prepared by the above-described method for preparing composite geotextile.

[0018] The present invention also provides a slope protection method based on composite geotextile, comprising the following steps: laying the composite geotextile prepared by the composite geotextile preparation method on the slope, with the base layer facing the slope soil, and sowing Dichondra repens seeds on the surface layer.

[0019] As a further improvement of the present invention, the sowing operation is as follows: Dichondra repens seeds are mixed with binder, water-retaining agent, potassium sulfate, calcium phosphate, urea, pH adjuster, and water in a certain proportion, and then sprayed onto the composite geotextile surface to form a 2-4 cm soil layer. Microorganisms in the soil can decompose urea to provide carbonate ions, which then react with calcium ions to form calcium carbonate precipitate.

[0020] The slope protection method initially utilizes a composite geotextile made of modified jute fiber and sugarcane fiber for slope protection. The modified jute fiber, serving as the base and surface layers, adsorbs microorganisms in the soil, inducing calcium carbonate precipitation, filling the pores of non-cohesive soil, reducing soil infiltration, and stabilizing the slope. The sugarcane fiber in the middle layer is a biodegradable material. During degradation, it enhances soil strength, reinforces the slope, and provides nutrients for Dichondra repens, promoting its growth. Because Dichondra repens is cold-resistant, drought-resistant, disease-resistant, pollution-resistant, grows vigorously, and has a well-developed root system, it can prevent rainwater infiltration and soil erosion. Furthermore, the roots of Dichondra repens can penetrate the needle-punched nonwoven composite geotextile, making the roots more firmly bonded to the soil, further reinforcing the slope. In the later stages, Dichondra repens and modified jute fiber can be used together for slope protection.

[0021] The beneficial effects of this invention are:

[0022] 1. This invention utilizes composite geotextile for the initial reinforcement of slopes. As time progresses, sugarcane fibers gradually degrade, and the degraded sugarcane fibers enhance soil strength, thus reinforcing the slope. Simultaneously, because the degraded sugarcane fibers are weakly acidic, the degradation process also promotes the growth of Dichondra repens. After growth is complete, Dichondra repens and composite geotextile are used together for slope protection. In the later stages, Dichondra repens and modified jute fibers are primarily used for slope reinforcement. Therefore, this slope protection method achieves good slope protection throughout the entire process, and compared to traditional reinforcement methods, it is cheaper, easier to construct, and causes less air pollution.

[0023] 2. By modifying jute fibers to enhance their spinnability and surface roughness, the lifespan of composite geotextiles with modified jute fibers as the outer layer can be increased. At the same time, due to the increased surface roughness, the modified jute fibers have a more significant effect on adsorbing microorganisms in the soil. They can utilize microorganisms to induce calcium carbonate precipitation, thereby reducing the pore volume between non-cohesive soils to a certain extent, reducing soil infiltration rate, increasing soil water retention capacity, and making it more conducive to vegetation growth, thus achieving the purpose of reinforcing slopes. Attached Figure Description

[0024] Figure 1 The results are from scanning electron microscopy of unmodified jute fibers.

[0025] Figure 2 The results are obtained from scanning electron microscopy of modified jute fibers. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0027] It should also be noted that, in order to avoid obscuring the present invention with unnecessary details, only the structures and / or processing steps closely related to the present invention are shown in the accompanying drawings, while other details that are not closely related to the present invention are omitted.

[0028] Additionally, it should be noted that the terms “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0029] Example 1

[0030] This embodiment provides a slope protection method based on composite geotextile, including the following steps:

[0031] S1. Place jute fiber in laccase at pH 5.0 and a concentration of 1.5% and enzymatically hydrolyze it at 60°C for 2 hours, wherein the mass ratio of jute fiber to laccase is 1:20. Then, wash the jute fiber treated with laccase with ethanol and water to remove dust from the fiber surface, and then dry it in an oven at 80°C. Next, soak the dried jute fiber in boiling water for 2 hours, then rinse off the chemical substances on the fiber surface with deionized water, and finally dry it (at 60°C) to obtain modified jute fiber.

[0032] S2. Due to the significant differences in properties of the modified jute fibers after processing, the modified jute fibers are first mixed in a bale-gripping machine, then opened in an opening machine, and finally carded into a jute fiber web using a carding machine. Using the jute fiber web as the base layer, sugarcane fibers are evenly laid on the base layer as the intermediate layer, and then the jute fiber web is laid on top of the sugarcane fibers as the surface layer to form a composite structure. This composite structure is then placed in a needle-punching machine to produce a unit area mass of 780 g / cm³. 2 The composite geotextile has a base layer, intermediate layer and surface layer thickness ratio of 1:3:1, that is, the thicknesses of the base layer, intermediate layer and surface layer are 2.3, 6.9 and 2.3 mm respectively;

[0033] S3. Lay the composite geotextile obtained in step S2 on the slope, with the base layer facing the slope soil, and sow Dichondra repens seeds on the surface layer. Before sowing, mix the Dichondra repens seeds with binder, water-retaining agent, potassium sulfate, calcium phosphate, urea, pH adjuster, and water in a certain proportion, and then spray the mixture onto the surface layer of the composite geotextile to form a 3m soil layer. The ratio of urea, calcium phosphate, potassium sulfate, and pH adjuster is 2:2:3:1, and the sowing amount of Dichondra repens seeds is 12g / m². 2 The specific amounts of binder and water-retaining agent used are adjusted according to the existing planting conditions of Dichondra repens. During the growth process of Dichondra repens, regular watering and fertilization are carried out to ensure the growth of the vegetation. The binder is polyacrylamide, the water-retaining agent is sodium polyacrylate, and the pH adjuster is lime.

[0034] Examples 2-4

[0035] Examples 2-4 each provide a slope protection method based on composite geotextile. Compared with Example 1, Example 2 reduces the unit area mass of the composite geotextile in step S2 from 780 g / m². 2 Adjusted to 920g / m 2 In Examples 3 and 4, the thickness ratio of the base layer, intermediate layer and top layer in step S2 was adjusted from 1:3:1 to 1:4:1 and 1:5:1, respectively. The remaining steps were the same as in Example 1 and will not be repeated here.

[0036] Comparative Examples 1-2

[0037] Comparative Examples 1 and 2 respectively provide a slope protection method based on composite geotextile. Compared with Example 1, Comparative Example 1 reduces the unit area mass of the composite geotextile in step S2 from 780 g / m². 2 Adjusted to 410g / m 2 The remaining steps are the same as in Example 1, and will not be repeated here.

[0038] In Comparative Example 2, no composite geotextile was laid; instead, Dichondra repens seeds were sown on the slope using the same sowing method as in Example 1.

[0039] Comparative Example 3

[0040] Comparative Example 3 provides a slope protection method based on composite geotextile. Compared with Example 1, Comparative Example 3 adjusts the thickness ratio of the base layer, intermediate layer and surface layer in step S2 to 1:2:1. The remaining steps are the same as in Example 1 and will not be repeated here.

[0041] Comparative Example 4

[0042] Comparative Example 4 provides a slope protection method based on composite geotextile. Compared with Example 1, Comparative Example 4 replaces sugarcane fiber with straw fiber. The remaining steps are the same as in Example 1 and will not be repeated here.

[0043] The linear density, breaking strength, and elongation at break of the jute fibers in Example 1 before and after bio-enzymatic treatment were measured, and the results are shown in Table 1. The morphology of the jute fibers before and after modification was examined using scanning electron microscopy, and the results are as follows: Figure 1 and Figure 2 As shown.

[0044] Table 1. Results of relevant parameters of jute fiber before and after bio-enzymatic treatment.

[0045]

[0046] As shown in Table 1, after treatment with bio-enzymes, the linear density of jute fiber increased by 44.25%, the breaking strength increased by 56.52%, the breaking elongation increased by 42.58%, and the spinnability of jute fiber was greatly increased.

[0047] like Figure 1 and Figure 2 As shown, after modification, the surface roughness of jute fiber increases significantly, which is more conducive to the attachment of microorganisms. This facilitates the use of microorganisms to induce calcium carbonate precipitation, reducing the pore volume between non-cohesive soils, decreasing soil infiltration rate, and increasing soil water retention capacity. This can achieve the purpose of reinforcing slopes while making the preparation more conducive to growth.

[0048] Detection Example 1

[0049] The slope protection methods described in Examples 1-4 and Comparative Examples 1-4 resulted in an average bulk density of 1.19 g / cm³ for a composition consisting of 40 wt% gravel, 40 wt% sand, and 20 wt% silt and clay. 3 The slope was reinforced.

[0050] Once the Dichondra repens has matured, the plant growth of Examples 1 and 2 and Comparative Examples 1 and 2, as well as the amount of soil erosion in Examples 1 and 2 and Comparative Examples 1 and 2 under a rainfall intensity of 100 mm / d, were measured. The results are shown in Table 2.

[0051] Table 2. Plant growth and soil erosion detection results in Examples 1 and 2 and Comparative Examples 1 and 2.

[0052]

[0053] In Examples 1 and 2, the germination rate of Dichondra repens was greater than 90%, the plant weight was greater than 155g, and the vegetation coverage reached 87%. When the unit area mass of the composite geotextile was low or when no composite geotextile was used, the growth of Dichondra repens in Comparative Examples 1 and 2 was significantly worse. Furthermore, the soil erosion in Examples 1 and 2 was significantly lower than in Comparative Examples 1 and 2, indicating that the slope protection method of this invention can effectively reinforce slopes.

[0054] The vegetation coverage of the slopes in Examples 3-4 and Comparative Example 3 was tested, and the results are shown in Table 3.

[0055] Table 3 shows the vegetation cover results of the slopes in Examples 3-4 and Comparative Example 3.

[0056]

[0057] When the thickness ratio of the base layer, intermediate layer, and surface layer is 1:3:1, the vegetation coverage can reach 87%. As the proportion of the intermediate layer thickness increases, the vegetation coverage significantly increases. This may be because the weakly acidic degradation of sugarcane fiber promotes the growth of Dichondra repens, and the sugarcane fiber provides some nutrients to Dichondra repens during degradation. When the proportion of the intermediate layer thickness is too small, the vegetation coverage decreases significantly. Since modified jute fiber plays a role in reinforcing the slope throughout the entire slope protection process, if the proportion of the intermediate layer thickness is too high, resulting in insufficient thickness of the surface and base layers, it may affect the slope reinforcement effect to some extent.

[0058] The specific growth of the plants in Example 1 and Comparative Example 4 was tested, and the results are shown in Table 4.

[0059] Table 4. Specific growth conditions of plants in Example 1 and Comparative Example 4.

[0060]

[0061] Compared with Example 1, in Comparative Example 4, after replacing sugarcane fiber with straw fiber, the height, biomass, leaf area, root length and germination rate of Dichondra repens were all relatively reduced. The overall decline in the growth of Dichondra repens may affect the later reinforcement effect of the plant on the slope.

[0062] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for preparing a composite geotextile for slope protection, characterized in that, Includes the following steps: S1. Modified jute fiber is obtained by sequentially treating jute fiber using a bio-enzymatic method and a hydrothermal method. The bio-enzymatic method involves placing jute fiber in laccase at a pH of 5-6 and a concentration of 1-2%, and enzymatically hydrolyzing it at 60-70℃ for 1.5-2.5 hours, wherein the mass ratio of jute fiber to laccase is 1:18-1:

22. The hydrothermal method involves washing and drying the jute fiber treated by the bio-enzymatic method, then soaking it in boiling water for 1.5-3.5 hours, followed by washing and drying to obtain the modified jute fiber. The drying temperature is 60-80℃. S2. Using the modified jute fiber obtained in step S1 as the base layer, sugarcane fiber is laid on the base layer as the intermediate layer, and then the modified jute fiber is laid on the sugarcane fiber as the surface layer, and a composite geotextile with a three-layer composite structure of modified jute fiber-sugarcane fiber-modified jute fiber is woven. The composite geotextile is laid on the slope with the base layer facing the slope soil, and Dichondra repens seeds are sown on the surface layer.

2. The method for preparing the composite geotextile for slope protection according to claim 1, characterized in that: In step S2, the thickness ratio of the base layer, intermediate layer and top layer is 1:3-5:

1.

3. The method for preparing the composite geotextile for slope protection according to claim 2, characterized in that: In step S2, the unit area mass of the composite geotextile is 750-950 g / m². 2 .

4. The method for preparing the composite geotextile for slope protection according to claim 3, characterized in that: In step S2, the textile process is a needle punching process.

5. The method for preparing the composite geotextile for slope protection according to claim 1, characterized in that: The sowing operation is as follows: mix Dichondra repens seeds with binder, water-retaining agent, potassium sulfate, calcium phosphate, urea, pH adjuster and water in a certain proportion, and then spray them on the composite geotextile surface to form a soil layer of 2-4 cm.

6. A composite geotextile, characterized in that, The composite geotextile is prepared according to the preparation method described in claim 4.

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