Preparation method and preparation device of composite geotechnical cloth and geotechnical cloth

Abstract

The invention provides a preparation method and a preparation device of a composite geotextile and the geotextile. The preparation method specifically comprises the following steps: preparing a polypropylene filament non-woven geotextile, a short fiber needle-punched geotextile and a filament geotextile; placing the short fiber needle-punched geotextile between the polypropylene filament non-woven geotextile and the filament geotextile; needling the three layers of geotechnical cloth through needling equipment, so that short fibers of the short fiber needle-punched geotechnical cloth are respectively wound with the polypropylene filament non-woven geotechnical cloth and the filament geotechnical cloth to form composite geotechnical cloth; in the conveying and rolling process of the composite geotechnical cloth, the hot-pressing compound machine is started, and the hot-pressing plate is driven to press the composite geotechnical cloth downwards; and the pressed composite geotechnical cloth is subjected to electrostatic adsorption, and then a winding completion stage is started. According to the preparation method and device of the composite geotechnical cloth and the geotechnical cloth, the polypropylene filament non-woven geotechnical cloth can be compounded with the filament geotechnical cloth in a needling mode, and the performance of the composite geotechnical cloth is improved.

Description

Technical Field

[0001] This invention belongs to the field of geotextile technology, specifically relating to a method and apparatus for preparing composite geotextile and the geotextile itself. Background Technology

[0002] Geotextiles are permeable geosynthetic materials made of synthetic fibers through needle punching or weaving. They are widely used in projects involving small-diameter sediments and high stress, such as landfills, water conservancy projects, ports, waterways, railways, and highways. Among them, polypropylene filament nonwoven geotextiles are increasingly widely used in various projects due to their excellent abrasion resistance and corrosion resistance. Filament-based geotextiles are geotextiles prepared through a specific process, featuring a double-gradient structure that provides better performance in geosynthetic applications.

[0003] However, in the production process of composite geotextiles, due to the need for heat treatment, conventional needle punching methods cannot be used to combine polypropylene filament nonwoven geotextiles with filament geotextiles. Currently, traditional composite geotextile preparation methods struggle to solve the problem of combining polypropylene filament nonwoven geotextiles with filament geotextiles, resulting in limited product performance and an inability to fully utilize the advantages of both materials. Specifically, existing composite geotextile preparation methods have the following problems: Existing preparation equipment requires manual bonding of multiple geotextile sheets before winding, increasing the workload; furthermore, during the transport of polypropylene filament nonwovens and filament geotextiles, dust in the air easily adheres to the surface of the double-gradient fibers on one side of the polypropylene filament nonwovens and the filament geotextile, leading to loose adhesion during later composite bonding, resulting in partial delamination, reduced strength, and weakened impermeability in the composite geotextile layout, affecting the overall quality and service life of the product. Summary of the Invention

[0004] The purpose of this invention is to provide a method and apparatus for preparing composite geotextile, as well as the geotextile itself, which solves the problem that polypropylene filament nonwoven geotextile cannot be combined with filament geotextile by needle punching, thereby improving the performance of the composite geotextile.

[0005] A method for preparing a composite geotextile specifically includes the following steps:

[0006] Step S1: Prepare polypropylene filament nonwoven geotextile, short fiber needle-punched geotextile and filament geotextile.

[0007] Step S2: Place the short-fiber needle-punched geotextile between the polypropylene filament nonwoven geotextile and the filament geotextile.

[0008] Step S3: The three layers of geotextile are needle-punched using a needle-punching device, so that the short fibers of the short fiber needle-punched geotextile are wrapped with the polypropylene filament nonwoven geotextile and the filament geotextile respectively to form a composite geotextile.

[0009] Step S4: During the transmission and winding process of the composite geotextile, start the hot press composite machine and drive the hot press plate to press down on the composite geotextile.

[0010] Step S5: Electrostatic adsorption is performed on the compressed composite geotextile, followed by the winding stage.

[0011] In step S1, by mass percentage, before preparing the polypropylene filament nonwoven geotextile, 1-5% glass fiber, 2-6% modified calcium sulfate whiskers and 2-4% anti-aging masterbatch are added to the polypropylene particles.

[0012] Among them, (glass fiber + modified calcium sulfate whiskers) / anti-aging masterbatch = 1-5.

[0013] In step S3, during the acupuncture process, the acupuncture depth is 10-50 mm, and the acupuncture density is 100-500 needles / m. 2 .

[0014] In step S4, before the composite geotextile reaches the hot-pressing composite machine, a water-based polyurethane composite emulsion containing nano-TiO2 and graphene oxide is sprayed onto the surface of the composite geotextile using a spraying machine. The nano-TiO2 content is 2-8% and the graphene oxide content is 1-5% by mass percentage.

[0015] Among them, (nano TiO2 + graphene oxide) / anti-aging masterbatch = 1-6.

[0016] A composite geotextile preparation apparatus includes a support frame, on which, from left to right, are arranged the following:

[0017] Release components for laying polypropylene filament nonwoven geotextiles, short fiber needle-punched geotextiles and filament geotextiles.

[0018] The bonding assembly is used to tightly bond polypropylene filament nonwoven geotextile, short fiber needle-punched geotextile and filament geotextile together.

[0019] Needle punching equipment is used to wrap short fibers of short fiber needle-punched geotextile with polypropylene filament nonwoven geotextile and filament geotextile respectively to form composite geotextile.

[0020] Spraying equipment is used to spray a water-based polyurethane composite emulsion containing nano-TiO2 and graphene oxide onto the surface of the composite geotextile.

[0021] Hot press laminating machine: Start the hot press laminating machine and drive the hot press plate to press down the composite geotextile;

[0022] Electrostatic adsorption equipment is used to adsorb and clean dust, loose material, etc. on composite geotextiles;

[0023] The winding assembly enables the winding of the composite geotextile.

[0024] The release assembly includes an upper release roller, a middle release roller, and a lower release roller arranged parallel to each other from top to bottom. An upper synchronous pulley is coaxially arranged at the outer end of the upper release roller, a middle synchronous pulley is coaxially arranged at the outer end of the middle release roller, and a lower synchronous pulley is coaxially arranged at the outer end of the lower release roller. The upper synchronous pulley is connected to the middle synchronous pulley via an upper synchronous belt, and the middle synchronous pulley is connected to the lower synchronous pulley via a lower synchronous belt. One end of the upper release roller is also connected to a release motor.

[0025] The needle punching equipment includes a geotextile needle punching machine and bonding components respectively arranged on both sides of the geotextile needle punching machine. The bonding components include an upper rotating roller and a lower rotating roller arranged parallel to each other, an upper gear coaxially connected to the outer end of the upper rotating roller, and a lower gear coaxially connected to the outer end of the lower rotating roller. The upper gear and the lower gear are meshed with each other. The upper rotating roller or the lower rotating roller is connected to a servo motor.

[0026] The take-up assembly includes a horizontally arranged take-up roller and a take-up motor coaxially connected to the outer end of the take-up roller.

[0027] A composite geotextile includes a polypropylene filament nonwoven geotextile layer, a short fiber needle-punched geotextile layer, and a filament geotextile layer arranged sequentially; the short fibers of the short fiber needle-punched geotextile layer are respectively wound with the polypropylene filament nonwoven geotextile layer and the filament geotextile layer to form a composite structure.

[0028] The short fibers of the short fiber needle-punched geotextile layer are one or more of polyester, acrylic, nylon, and polypropylene.

[0029] The technical details not described in this solution are based on the conventional understanding of those skilled in the art and can be implemented in conjunction with existing technologies. Therefore, they will not be elaborated further here.

[0030] This invention achieves the following significant effects:

[0031] (1) This invention solves the problem that polypropylene filament nonwoven geotextile cannot be combined with filament geotextile by adding a short fiber needle-punched geotextile layer between polypropylene filament nonwoven geotextile and filament geotextile, and uses the needle-punching process to make the short fiber wrapped and composite with the other two geotextile layers, thereby improving the overall performance of the composite geotextile.

[0032] Specifically, composite geotextiles combine the wear resistance and corrosion resistance of polypropylene filament nonwoven geotextiles, the high strength of filament geotextiles, and the good flexibility and entanglement properties of short-fiber needle-punched geotextiles with other materials, enabling them to better perform their functions of isolation, filtration, drainage, and reinforcement in engineering applications, thus extending the service life of projects.

[0033] (2) In this scheme, glass fiber and modified calcium sulfate whiskers are mixed into the polypropylene matrix and high-strength nonwoven fabric is prepared by melt spinning. The mechanical properties are greatly improved by utilizing the fiber reinforcement principle. Anti-aging masterbatch is added to the spinning raw material. Polypropylene (PP) fiber containing anti-aging masterbatch can effectively slow down fiber breakage and thermal stability decline, thus delaying material aging in essence and maintaining the compactness of its structure.

[0034] By modifying the surface of calcium sulfate whiskers, the surface energy is reduced and the interfacial affinity between them and the organic matrix is ​​improved. This not only enhances the uniformity of whisker dispersion in the organic matrix and strengthens the interfacial bonding force between the whiskers and the matrix, but also further optimizes the overall performance of the composite material.

[0035] (3) In this scheme, a polyvinylidene fluoride (PVDF) composite emulsion containing nano TiO2 (UV shielding agent) and graphene oxide (GO) is coated on the surface of the geotextile. This microporous membrane can not only shield UV rays, but also fill the micropores between fibers, further improving the seepage prevention performance. Experimental data show that the geotextile treated with anti-aging masterbatch and TiO2 only decreased by 26.55% in longitudinal tensile strength retention rate after UV aging, which is far better than the untreated sample. This is directly related to the seepage prevention integrity of the material under long-term use.

[0036] (4) For geotextiles with waterproof layers, hot pressing is used instead of simple adhesive. By precisely controlling the temperature (e.g., 100-220℃) and pressure of hot pressing, the interfaces of different materials partially melt and dissolve to form a solid whole, avoiding false welding and delamination caused by adhesive aging or improper welding temperature.

[0037] (5) The preparation method of the present invention is simple and easy to implement. By adding short fiber needle-punched geotextile, needle-punching treatment, hot-pressing composite machine and electrostatic adsorption process, the production of new composite geotextile is realized. The preparation device facilitates large-scale industrial production, and no special equipment is required in the production process, which reduces the production cost. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of the composite geotextile preparation equipment of the present invention.

[0039] Figure 2 This is a front view of the composite geotextile preparation equipment of the present invention.

[0040] Figure 3 This is a schematic diagram of the structure of the release component of the present invention.

[0041] The attached diagram is labeled as follows: 1. Support; 2. Lower release roller; 21. Lower synchronous pulley; 3. Middle release roller; 31. Middle synchronous pulley; 4. Upper release roller; 41. Upper synchronous pulley; 5. Release motor; 6. Lower rotating roller; 7. Upper rotating roller; 8. Servo motor; 9. Needle punching equipment; 10. Spraying equipment; 11. Hot press laminating machine; 12. Electrostatic adsorption equipment; 13. Rewinding roller; 14. Rewinding motor. Detailed Implementation

[0042] To more clearly illustrate the technical features of this solution, the following detailed implementation method will be used to explain the solution.

[0043] Example 1

[0044] A method for preparing a composite geotextile specifically includes the following steps:

[0045] Step S1: Prepare polypropylene filament nonwoven geotextile, short fiber needle-punched geotextile and filament geotextile.

[0046] Step S2: Place the short-fiber needle-punched geotextile between the polypropylene filament nonwoven geotextile and the filament geotextile.

[0047] Step S3: The three-layer geotextile is needle-punched by the needle-punching device 9, so that the short fibers of the short fiber needle-punched geotextile are wrapped with the polypropylene filament nonwoven geotextile and the filament geotextile respectively to form a composite geotextile.

[0048] Step S4: During the transmission and winding process of the composite geotextile, start the hot press composite machine 11 and drive the hot press plate to press down on the composite geotextile.

[0049] Step S5: Electrostatic adsorption is performed on the compressed composite geotextile, followed by the winding stage.

[0050] In step S3, during the acupuncture process, the acupuncture depth is 10-50 mm, and the acupuncture density is 100-500 needles / m. 2 .

[0051] To further illustrate the superior technical effects of the composite geotextile in Example 1 of this scheme, the following two test groups and one control group were designed:

[0052] Experimental Group 1: In this Example 1, samples with a weight of 200g / m³ were prepared. 2 The polypropylene filament nonwoven geotextile has a filament diameter of 0.1 mm and a basis weight of 150 g / m². 2 Short-fiber needle-punched geotextile, the short fibers are polyester; weight is 300 g / m². 2The geotextile has long filaments with a filament diameter of 0.2 mm.

[0053] Short fiber needle-punched geotextile is placed between polypropylene filament nonwoven geotextile and filament geotextile.

[0054] Acupuncture was performed using a needle acupuncture device, with a needle depth of 20 mm and a needle density of 200 needles / m. 2 The short fibers of the short-fiber needle-punched geotextile are wrapped with polypropylene filament nonwoven geotextile and filament geotextile respectively to obtain a composite geotextile.

[0055] Experimental group 2: Prepared weight of 300g / m 2 Polypropylene filament nonwoven geotextile with filament diameter of 0.2 mm and a basis weight of 200 g / m². 2 Short-fiber needle-punched geotextile, the short fibers are polypropylene; weight is 400 g / m². 2 The geotextile has a filament diameter of 0.3 mm.

[0056] Three layers of geotextile were placed as described in test group 1 above. The needle-punching depth was adjusted to 30 mm, and the needle-punching density was 300 needles / m. 2 The composite geotextile is obtained by needle punching.

[0057] Comparative Group 1: Polypropylene filament nonwoven geotextile and filament geotextile were hot-pressed together using a traditional method, without adding a short-fiber needle-punched geotextile layer. The performance of the composite geotextiles prepared in Experimental Group 1 and Experimental Group 2 was compared with that of the product in Comparative Group 1, and the results are shown in Table 1.

[0058] Table 1 Performance test results of composite geotextiles in test group 1, test group 2 and control group 1

[0059] Test Project Experimental group 1 Experimental group 2 Comparison Group 1 Tensile strength (kN / m) 15 18 10 Tear strength (N) 200 250 150 Corrosion resistance (simulated acid and alkali environment, 100 days) No significant changes No significant changes Slight corrosion

[0060] The test results show that the composite geotextile prepared by this invention is superior to products prepared by traditional methods in terms of tensile strength, tear strength and corrosion resistance.

[0061] Example 2

[0062] Based on test group 2 in Example 1, this Example 2 is introduced.

[0063] In step S1, before preparing the polypropylene filament nonwoven geotextile, 1-5% glass fiber, 2-6% modified calcium sulfate whiskers and 2-4% anti-aging masterbatch are added to the polypropylene particles by mass percentage; wherein, (glass fiber + modified calcium sulfate whiskers) / anti-aging masterbatch = 1-5.

[0064] In this Example 2, the following sets of experiments were designed to verify the effects of the addition of glass fiber, modified calcium sulfate whiskers, and anti-aging masterbatch on the performance of composite geotextile.

[0065] Experimental Group A: 1% glass fiber, 6% modified calcium sulfate whiskers, 2% anti-aging masterbatch, and the remainder polypropylene;

[0066] Experimental Group B: 3% glass fiber, 4% modified calcium sulfate whiskers, 3% anti-aging masterbatch, and the remainder is polypropylene;

[0067] Experimental group C: 5% glass fiber, 2% modified calcium sulfate whiskers, 4% anti-aging masterbatch, and the remainder is polypropylene;

[0068] The composite geotextile products prepared in experimental groups A, B, and C were subjected to performance tests, and the results are shown in Table 2.

[0069] Table 2 Performance test results of composite geotextiles in test groups A, B, and C

[0070] Test Project Experimental group A Experimental group B Experimental group C Tensile strength (kN / m) 19 23 24 Tear strength (N) 253 259 261 Corrosion resistance (simulated acid and alkali environment, 100 days) No significant changes No significant changes No significant changes

[0071] As can be seen from Table 2, the tensile strength and tear strength of experimental groups A, B, and C are increasing, but the rate of increase is slowing down. This indicates that the mechanical properties can be significantly improved by using the fiber reinforcement principle. In addition, since the content of modified calcium sulfate whiskers decreases, it indicates that the surface modification of modified calcium sulfate whiskers can enhance the interfacial bonding force between the whiskers and the matrix, thereby optimizing the overall performance of the composite material.

[0072] In addition, adding anti-aging masterbatch to the spinning raw material can effectively slow down fiber breakage and thermal stability decline in polypropylene (PP) fibers containing anti-aging masterbatch, thereby delaying material aging and maintaining the compactness of its structure.

[0073] Example 3

[0074] Based on experimental group C in Examples 1 and 2, this Example 3 is introduced.

[0075] In step S4, before the composite geotextile reaches the hot-pressing composite machine 11, a water-based polyurethane composite emulsion containing nano-TiO2 and graphene oxide is sprayed onto the surface of the composite geotextile using a spraying machine. The nano-TiO2 content is 2-8% and the graphene oxide content is 1-5% by mass percentage.

[0076] Among them, (nano TiO2 + graphene oxide) / anti-aging masterbatch = 1-6.

[0077] In this Example 3, the following sets of experiments were designed to verify the effects of adding nano-TiO2, graphene oxide, and anti-aging masterbatch on the performance of composite geotextile.

[0078] Experimental group C1: 2% nano-TiO2 content, 5% graphene oxide content, 2% anti-aging masterbatch, and the remainder is polypropylene;

[0079] Experimental group C2: 5% nano-TiO2 content, 3% graphene oxide content, 3% anti-aging masterbatch, and the remainder is polypropylene;

[0080] Experimental group C3: 8% nano-TiO2 content, 1% graphene oxide content, 4% anti-aging masterbatch, and the remainder is polypropylene;

[0081] The composite geotextile products prepared by experimental groups C1, C2 and C3 were subjected to performance tests, and the results are shown in Table 3.

[0082] Table 3 Performance test results of composite geotextiles in test groups C1, C2 and C3

[0083] Test Project Experimental group C1 Experimental group C2 Experimental group C3 Tensile strength after UV treatment (kN / m) 22 23 22 Tear strength (N) after UV treatment 194 196 197 Corrosion resistance (simulated acid and alkali environment, 100 days) No significant changes No significant changes No significant changes

[0084] As can be seen from Table 3, the tensile strength and tear strength have increased to a certain extent and are generally better than the data in Example 2. This indicates that coating the surface of geotextile with a composite emulsion of polyvinylidene fluoride (PVDF) containing nano-TiO2 (UV shielding agent) and graphene oxide (GO) results in a longitudinal fracture strength retention rate of only 25%-27% after UV aging, which is far better than the untreated sample. This is directly related to the impermeability integrity of the material under long-term use.

[0085] It should be noted that, in order to reduce the cost of testing, the parameters that are not specifically defined in the various embodiments of this scheme are all determined based on the minimum value of the corresponding data range, and the components that are not specifically defined are tested according to the lowest market price; these will not be described in detail here.

[0086] Example 4

[0087] See Figures 1-3 A composite geotextile preparation device includes a support 1, on which, from left to right, are arranged the following:

[0088] Release components for laying polypropylene filament nonwoven geotextiles, short fiber needle-punched geotextiles and filament geotextiles.

[0089] The bonding assembly is used to tightly bond polypropylene filament nonwoven geotextile, short fiber needle-punched geotextile and filament geotextile together.

[0090] Needle punching equipment 9 is used to wrap short fibers of short fiber needle-punched geotextile with polypropylene filament nonwoven geotextile and filament geotextile respectively to form composite geotextile.

[0091] Spraying equipment 10 sprays an aqueous polyurethane composite emulsion containing nano-TiO2 and graphene oxide onto the surface of the composite geotextile.

[0092] Hot press laminating machine 11, start hot press laminating machine 11 and drive hot press plate to press down the composite geotextile;

[0093] Electrostatic adsorption device 12 is used to adsorb and clean dust, loose material, etc. on composite geotextile.

[0094] The winding assembly enables the winding of the composite geotextile.

[0095] The release assembly includes an upper release roller 4, a middle release roller 3, and a lower release roller 2 arranged in parallel from top to bottom. The outer end of the upper release roller 4 is coaxially provided with an upper synchronous pulley 41, the outer end of the middle release roller 3 is coaxially provided with a middle synchronous pulley 31, and the outer end of the lower release roller 2 is coaxially provided with a lower synchronous pulley 21. The upper synchronous pulley 41 is connected to the middle synchronous pulley 31 via an upper synchronous belt, and the middle synchronous pulley 31 is connected to the lower synchronous pulley 21 via a lower synchronous belt. One end of the upper release roller 4 is also connected to a release motor 5.

[0096] The needle punching device 9 includes a geotextile needle punching machine and bonding components respectively arranged on both sides of the geotextile needle punching machine. The bonding components include an upper rotating roller 7 and a lower rotating roller 6 arranged parallel to each other, an upper gear coaxially connected to the outer end of the upper rotating roller 7, and a lower gear coaxially connected to the outer end of the lower rotating roller 6. The upper gear and the lower gear are meshed with each other. The upper rotating roller 7 or the lower rotating roller 6 is connected to a servo motor 8.

[0097] The winding assembly includes a horizontally arranged winding roller 13 and a winding motor 14 coaxially connected to the outer end of the winding roller 13.

[0098] Example 5

[0099] A composite geotextile includes a polypropylene filament nonwoven geotextile layer, a short fiber needle-punched geotextile layer, and a filament geotextile layer arranged sequentially; the short fibers of the short fiber needle-punched geotextile layer are respectively wound with the polypropylene filament nonwoven geotextile layer and the filament geotextile layer to form a composite structure.

[0100] The short fibers in the short-fiber needle-punched geotextile layer are polyester.

[0101] The technical features of this invention not described can be implemented by or using existing technology, and will not be repeated here. Of course, the above description is not a limitation of this invention, and this invention is not limited to the examples above. Any changes, modifications, additions or substitutions made by those skilled in the art within the scope of this invention should also be within the protection scope of this invention.

Claims

1. A method for preparing a composite geotextile, characterized in that, Specifically, the steps include the following: Step S1: Prepare polypropylene filament nonwoven geotextile, short fiber needle-punched geotextile and filament geotextile. Step S2: Place the short-fiber needle-punched geotextile between the polypropylene filament nonwoven geotextile and the filament geotextile. Step S3: The three-layer geotextile is needle-punched by the needle-punching device (9) so that the short fibers of the short fiber needle-punched geotextile are wrapped with the polypropylene filament nonwoven geotextile and the filament geotextile respectively to form a composite geotextile. Step S4: During the transmission and winding of the composite geotextile, start the hot press composite machine (11) and drive the hot press plate to press down on the composite geotextile; Step S5: Electrostatic adsorption is performed on the compressed composite geotextile, followed by the winding stage.

2. A method for preparing a composite geotextile according to claim 1, characterized in that, In step S1, by mass percentage, before preparing the polypropylene filament nonwoven geotextile, 1-5% glass fiber, 2-6% modified calcium sulfate whiskers and 2-4% anti-aging masterbatch are added to the polypropylene particles. Among them, (glass fiber + modified calcium sulfate whiskers) / anti-aging masterbatch = 1-5.

3. A method for preparing a composite geotextile according to claim 1, characterized in that, In step S3, during the acupuncture process, the acupuncture depth is 10-50 mm, and the acupuncture density is 100-500 needles / m. 2 .

4. A method for preparing a composite geotextile according to claim 1, characterized in that, In step S4, before the composite geotextile reaches the hot-pressing composite machine (11), a water-based polyurethane composite emulsion containing nano-TiO2 and graphene oxide is sprayed onto the surface of the composite geotextile using a spraying machine. The nano-TiO2 content is 2-8% and the graphene oxide content is 1-5% by mass percentage. Among them, (nano TiO2 + graphene oxide) / anti-aging masterbatch = 1-6.

5. A composite geotextile preparation apparatus, employing a composite geotextile preparation method according to any one of claims 1-4, comprising a support (1), characterized in that, The bracket (1) is provided with the following items from left to right: Release components for laying polypropylene filament nonwoven geotextiles, short fiber needle-punched geotextiles and filament geotextiles. The bonding assembly is used to tightly bond polypropylene filament nonwoven geotextile, short fiber needle-punched geotextile and filament geotextile together. The needle punching device (9) is used to wrap the short fibers of the short fiber needle punched geotextile with polypropylene filament nonwoven geotextile and filament geotextile respectively to form a composite geotextile. Spraying equipment (10) sprays an aqueous polyurethane composite emulsion containing nano-TiO2 and graphene oxide onto the surface of the composite geotextile. Hot press composite machine (11), start the hot press composite machine (11) and drive the hot press plate to press down the composite geotextile; Electrostatic adsorption equipment (12) is used to adsorb and clean dust, loose material and other debris on composite geotextile. The winding assembly enables the winding of the composite geotextile.

6. The apparatus for preparing a composite geotextile according to claim 5, characterized in that, The release assembly includes an upper release roller (4), a middle release roller (3), and a lower release roller (2) arranged in parallel from top to bottom. The upper release roller (4) has an upper synchronous pulley (41) coaxially arranged at its outer end. The middle release roller (3) has a middle synchronous pulley (31) coaxially arranged at its outer end. The lower release roller (2) has a lower synchronous pulley (21) coaxially arranged at its outer end. The upper synchronous pulley (41) is connected to the middle synchronous pulley (31) via an upper synchronous belt. The middle synchronous pulley (31) is connected to the lower synchronous pulley (21) via a lower synchronous belt. One end of the upper release roller (4) is also connected to a release motor (5).

7. The apparatus for preparing a composite geotextile according to claim 5, characterized in that, The needle punching device (9) includes a geotextile needle punching machine and bonding components respectively arranged on both sides of the geotextile needle punching machine. The bonding components include an upper rotating roller (7) and a lower rotating roller (6) arranged in parallel to each other, an upper gear coaxially connected to the outer end of the upper rotating roller (7), and a lower gear coaxially connected to the outer end of the lower rotating roller (6). The upper gear and the lower gear mesh with each other. The upper rotating roller (7) or the lower rotating roller (6) is connected to a servo motor (8).

8. The apparatus for preparing a composite geotextile according to claim 5, characterized in that, The winding assembly includes a horizontally arranged winding roller (13) and a winding motor (14) coaxially connected to the outer end of the winding roller (13).

9. A composite geotextile, characterized in that, It includes a polypropylene filament nonwoven geotextile layer, a short fiber needle-punched geotextile layer and a filament geotextile layer arranged in sequence; the short fibers of the short fiber needle-punched geotextile layer are wrapped with the polypropylene filament nonwoven geotextile layer and the filament geotextile layer respectively to form a composite structure.

10. A composite geotextile according to claim 9, characterized in that, The short fibers in the short fiber needle-punched geotextile layer are one or more of polyester, acrylic, nylon, and polypropylene.

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