ANTI-FILTRATION SCREEN

Abstract

This utility model relates to the field of anti-seepage devices and structures and can be used for screening soils and sealing the surfaces of various sites, pits, and other structures. The anti-seepage screen comprises a layer of bentonite, an intermediate layer of geotextile, a first layer of geomembrane, a first protective layer of geotextile, a drainage layer of 3D hydromat, a second layer of geomembrane, and a second protective layer of geotextile, arranged sequentially from bottom to top. The technical result of the utility model consists in increasing the reliability of the anti-seepage effect. 3 clauses, 1 fig.

Description

[0001] The utility model relates to the field of anti-seepage devices and structures, and can be used for screening soils and sealing the surfaces of various sites, pits and other structures.

[0002] A TWO-LAYER BARRIER STRUCTURE FOR LOADING GARBAGE is known from the prior art [CN207672630U, published 07 / 31 / 2018], including a base and a protective layer of compacted soil, characterized in that: a protective layer of compacted soil is arranged on the base, a pit is arranged in the middle of the protective layer of compacted soil, a first HDPE geomembrane and a first geotextile drainage mesh are successively laid on the protective layer of compacted soil, a lower exhaust pipe is laid on the first geotextile drainage mesh on one side of the pit, and a drainage layer for removing filtrate is laid in the pit on this side. The first geotextile drainage mesh and the second geotextile drainage mesh are covered with a second HDPE geomembrane. The second HDPE geomembrane is covered with nonwoven geotextile. The upper exhaust pipe is located on the nonwoven geotextile on the other side of the excavation pit.

[0003] The disadvantage of this design is that the screen that prevents filtration is made essentially in one layer, consisting of a geotextile drainage mesh covered with an HDPE geomembrane, and therefore damage to the geomembrane can lead to direct penetration of contaminants into the underlying layers without intercepting them.

[0004] The closest in technical essence is the STRUCTURE FOR PREVENTING SEALING IN A LANDFILL [CN218116568U, published on 23.12.2022], including a base layer, characterized in that the base layer is a soil layer with a compaction density of ≥93%, and further including, from the bottom up, a bentonite mat GCL, a secondary infiltration prevention layer, a first upper protective membrane layer, a filtrate detection layer, a lower protective membrane layer, a primary infiltration prevention layer, a second upper protective membrane layer, an auxiliary drainage layer, a filter layer, a backfill layer and a rainwater insulation layer, wherein the first upper protective membrane layer, the lower protective membrane layer and the second upper protective membrane layer are made of geotextile.

[0005] The main technical problem of the prototype is that the first upper protective layer, the lower protective layer and the second upper protective layer are made of geotextile, which reduces the screening mechanism to the operation of the primary infiltration prevention layer, while the secondary infiltration prevention layer and the geotextile protective layers do not provide a reliable backup anti-seepage circuit, in addition, the leachate detection system essentially monitors the integrity of only one primary barrier, which leads to the risk of not detecting possible leaks.

[0006] The purpose of the utility model is to eliminate the shortcomings of the prototype.

[0007] The technical result of the utility model is to increase the reliability of the anti-seepage effect.

[0008] The specified technical result is achieved due to the fact that the anti-seepage screen contains a layer of bentomate, an intermediate layer of geotextile, a first layer of geomembrane, a protective layer of geotextile, a drainage layer of 3D hydromat, a second layer of geomembrane and a second protective layer of geotextile, placed sequentially from bottom to top.

[0009] In particular, the thickness of the second layer of geomembrane is greater than the thickness of the first layer of geomembrane.

[0010] In particular, control pipes are laid above the bentomate layer.

[0011] In particular, the thickness of the first layer of geomembrane is 1-2mm.

[0012] In particular, the thickness of the second layer of geomembrane is 2-3mm.

[0013] In particular, the first layer of geomembrane and the second layer of geomembrane are laid with an overlap of 100-150 mm, and the geomembrane sheets are overlap-welded with hot air under pressure to form a double seam of 40-50 mm in width, with the creation of an intermediate channel to enable checking the quality of the seam.

[0014] Specifically, the first layer of geomembrane and the second layer of geomembrane are made of high-density polyethylene.

[0015] Specifically, the first layer of geomembrane and the second layer of geomembrane are made of low density polyethylene.

[0016] Brief description of drawings:

[0017] Fig. 1 shows a sectional view of the anti-seepage screen.

[0018] The figures show: 1 - bentomate layer; 2 - intermediate layer of geotextile; 3 - first layer of geomembrane, 4 - first protective layer of geotextile, 5 - drainage layer of 3D hydromat, 6 - second layer of geomembrane, 7 - second protective layer of geotextile.

[0019] Implementation of a utility model.

[0020] The anti-seepage screen is designed to create a multifunctional protective barrier, primarily in hydraulic, civil, and environmental engineering, such as isolating solid waste landfills, tailings ponds, settling basins, and creating anti-seepage curtains. The screen combines waterproofing, drainage, and load distribution functions.

[0021] The anti-seepage screen consists of a bentomate layer 1, an intermediate geotextile layer 2, a first geomembrane layer 3, a first protective geotextile layer 4, a drainage layer made of 3D hydromat 5, a second geomembrane layer 6 and a second protective geotextile layer 7, wherein the bentomate layer 1, the intermediate geotextile layer 2, the first geomembrane layer 3, the first protective geotextile layer 4, the drainage layer made of 3D hydromat 5, the second geomembrane layer 6 and the second protective geotextile layer 7 are fastened together at the edges. Fastening can be carried out either by means of fasteners such as metal staples and ties, or by soldering or welding, for example, with hot air. A method of stitching layers with a polymer or steel thread can also be used.

[0022] Bottom Layer - A layer of bentonite mat 1 in contact with the base of the landfill or site where the anti-seepage barrier is located. This layer is made of bentonite sealed between two layers of geotextile or geotextile and polyethylene film. Upon contact with water, the bentonite swells, forming a gel, which provides self-healing of minor damage and forms a primary anti-seepage barrier with a low filtration coefficient. Additionally, monitoring pipes can be installed above the bentonite layer 1, preferably between the bentonite layer 1 and the first layer of geomembrane 3, to detect filtrate leaks below the first layer of geomembrane 3.

[0023] Intermediate geotextile layer 2 is located directly over the bentomate layer 1. It is made of heat-bonded or needle-punched geotextile with a surface density of 300-600 g / m². This layer protects the overlying first layer of geomembrane 3 from possible localized indentations by bentomate particles 1. It is also necessary for additional load distribution and the creation of a sliding plane to compensate for possible foundation settlement.

[0024] The first layer of geomembrane 3 is the primary waterproofing barrier and is placed over the intermediate layer of geotextile 2. The first layer of geomembrane 3 is made of a polymer geomembrane, preferably high-density polyethylene (HDPE) or very low-density polyethylene (VLDPE), with a thickness of 1.0-2.0 mm. It provides high resistance to chemicals and absolute waterproofness. The first layer of geomembrane 3 is laid with an overlap of 100-150 mm, and the geomembrane sheets are overlap-welded with hot air under pressure to form a double seam 40-50 mm wide, with an intermediate channel created for seam quality inspection.

[0025] The first protective layer of geotextile 4 is located on top of the first layer of geomembrane 3. The first protective layer of geotextile 4 is similar to the intermediate layer of geotextile 2 and is necessary to protect the first layer of geomembrane 3 from mechanical damage (punctures, abrasion) from the overlying drainage layer made of 3D hydromat 5.

[0026] A 3D 5 hydromat drainage layer is placed above the first level of the waterproofing barrier, which consists of a bentonite layer 1, an intermediate geotextile layer 2, a first geomembrane layer 3, and a first protective geotextile layer 4. The 3D 5 hydromat drainage layer is made of a three-dimensional polymer mat (hydromat) with a three-dimensional structure, such as polyamide or polyethylene, forming a channel system. The primary function of this layer is to intercept and drain infiltration water that may accumulate above the first waterproofing screen, thereby reducing the hydrostatic pressure on it. This layer provides planar drainage.

[0027] The second layer of geomembrane 6 is the top primary waterproofing barrier, made of a polymer geomembrane, preferably high-density polyethylene (HDPE) or very low-density polyethylene (VLDPE), 2.0-3.0 mm thick. It forms a second, independent line of defense against the penetration of pollutants into the environment or, conversely, against the penetration of external water into the protected structure. This layer is also laid with an overlap of 100-150 mm. The geomembrane sheets are overlap-welded with hot air under pressure, creating a double seam 40-50 mm wide, with an intermediate channel created for seam quality inspection.

[0028] The second protective layer of geotextile 7 is the topmost layer of the structure. It is made of high-density (500-800 g / m²) and durable geotextile and serves to protect the upper geomembrane from damage during subsequent construction activities (soil and gravel placement, vehicle movement), act as a separator between the geomembrane and overlying fill materials, and reinforce the surface.

[0029] The impermeable screen is formed by sequentially laying each layer on the prepared base. It is critical to ensure tight contact between the layers without the formation of air pockets that could lead to local stress. The interaction of the layers provides a synergistic effect: the lower barrier, consisting of a layer of bentomate 1, an intermediate layer of geotextile 2, a first layer of geomembrane 3, and a first protective layer of geotextile 4, performs the primary waterproofing function, while the drainage layer of 3D hydromat 5, located between the two geomembranes (the first layer of geomembrane 3 and the second layer of geomembrane 6), functions as a leakage control and collection system. Any moisture that penetrates the upper barrier (the second geomembrane) will be intercepted and can be drained for monitoring. Similarly, moisture potentially migrating from below will be localized between the first geomembrane and the bentonite.In addition, protective layers of geotextile prevent damage to both the lower and upper waterproofing barriers from sharp particles in the contacting layers, ensuring the reliability and durability of the anti-seepage screen, just as duplicating the waterproofing barriers significantly increases the reliability and service life of the screen as a whole compared to single-layer solutions.

[0030] This design provides increased reliability in collecting filtrate and screening underlying soil layers, and also has increased cost-effectiveness and low material consumption compared to similar reusable solutions, for example, screens with asphalt covering.

[0031] Examples of implementation of the utility model.

[0032] In accordance with this utility model, examples of the implementation of an anti-seepage screen were implemented.

[0033] Example 1.

[0034] A seepage barrier was constructed for a solid waste landfill. It consisted of a self-healing sodium bentomate layer, with the first primary waterproofing barrier—a 1.5 mm thick high-density polyethylene (HDPE) geomembrane with double-welded seams—sandwiched between a 500 g / m² heat-bonded geotextile. A first protective layer of geotextile was placed over this membrane to protect against mechanical damage. Above the first waterproofing barrier was a drainage layer of 3D volumetric hydromat, creating a channel system to intercept and drain infiltration water. The drainage was covered with a 2.5 mm thick HDPE geomembrane, which formed a second independent line of defense. The structure was completed with an upper protective layer of durable needle-punched geotextile with a density of 600 g / m², designed to reinforce the surface and protect it from the overlying soil.A system of perforated monitoring pipes, placed between the bentonite and the first geomembrane, was integrated into the screen structure to monitor for potential leaks. At the edges of the screen, the layers were bonded together using hot air welding. The interaction of the layers provided a synergistic effect of duplicated waterproofing with active drainage and monitoring.

[0035] Example 2.

[0036] The impermeable screen was designed as a highly reliable double-barrier barrier for the bottom and slopes of the tailings storage facility. Its bottom layer consisted of a combined bentonite mat (bentonite sandwiched between geotextile and polyethylene film) with increased chemical resistance. Above this was a reinforced intermediate layer of 600 g / m² geotextile, which compensated for deformations in the base. The first waterproofing barrier was made of a flexible and chemically resistant 2.0 mm thick very-low-density polyethylene (VLDPE) geomembrane with extrusion seams, protected by a corresponding layer of geotextile. A central drainage layer of 3D hydromat formed a closed loop connected to drainage wells. The upper, second waterproofing barrier, designed to withstand abrasive impacts, was made of a 3.0 mm thick HDPE geomembrane.The top protective layer, made of high-density (800 g / m²) thermally bonded geotextile, provided resistance to crushing and distributed the load from the washed-in tailings. The layers were fastened together at the edges of the screen with metal staples. The overall structure consisted of an insulating system with duplicated chemical-resistant barriers and an active drainage-control layer between them.

[0037] Example 3.

[0038] The manufactured anti-seepage barrier provided a comprehensive solution for waterproofing and gas sealing the concrete base of an underground parking garage. Its bottom, contact layer consisted of bentomat with modified bentonite, effectively blocking the migration of gases and soil moisture. A separating intermediate layer of lightweight geotextile with a density of 300 g / m² prevented contact between the bentomat and the overlying membrane. The first waterproofing barrier was formed by a 1.0 mm thick HDPE geomembrane, protected by its own geotextile layer. Above this was a thin drainage layer of 3D hydromat, integrated into the building's perimeter drainage system to collect capillary moisture. The second waterproofing barrier was made of 2.0 mm thick HDPE geomembrane. The top protective layer of 500 g / m² geotextile provided protection against the subsequent placement of a concrete screed. At the edges of the screen, the layers were fastened together by stitching and binding with metal thread.The final design served as a single multi-layer screen, combining the functions of a gas curtain, duplicated waterproofing with controlled drainage of the inter-membrane space and mechanical protection.

[0039] The technical result of the utility model is to increase the reliability of the anti-seepage effect.

[0040] The stated technical result is achieved due to the fact that the anti-seepage screen contains a lower barrier consisting of a layer of bentomate, an intermediate layer of geotextile, a first layer of geomembrane and a first protective layer of geotextile, as well as a second layer of geomembrane located above the drainage layer, which forms a second independent line of defense, which directly increases reliability: in the event of hypothetical damage to the upper barrier, the lower barrier continues to perform its function.

[0041] Furthermore, a 3D hydromat drainage layer placed between two geomembranes helps contain any moisture that has leaked through the upper membrane, allowing it to be removed and any leaks to be documented, preventing the buildup of hydrostatic pressure and the hidden spread of filtrate. Similarly, moisture from below is contained between the first geomembrane and the bentomate, ensuring increased reliability during filtrate collection. The lower bentomate layer, capable of swelling and forming a gel, ensures self-healing of minor damage to the underlying layers and creates a primary anti-seepage barrier, complementing the anti-seepage effect of the first geomembrane layer. The intermediate, first protective, and second protective geotextile layers also prevent mechanical damage to both the lower and upper geomembranes from contacting the layers.Protection from damage during installation and operation directly increases the durability and reliability of the main waterproofing elements.

[0042] Furthermore, the geomembrane seams are constructed as double welds with an inspection channel, ensuring a highly reliable connection between the sheets and the ability to verify their quality, eliminating weak points in the primary barriers. Additionally, the optional installation of inspection pipes between the bentonite layer and the first geomembrane creates an additional integrity monitoring circuit for the lower barrier, further enhancing overall controllability and, therefore, the operational reliability of the system.

[0043] The claimed impermeable barrier offers a significantly higher level of reliability compared to the prototype. The prototype's reliability is based on the quality of the materials and the installation of a single barrier, while the reliability of the claimed solution is ensured by the duplication of barriers, the presence of an active control and drainage gap between them, targeted protection, and integrated monitoring equipment. This design makes the product fault-tolerant, repairable, and significantly more durable in challenging operating conditions, which fully corresponds to the stated technical result.

[0044] Thus, the stated impermeable screen provides increased reliability of screening against filtrate penetration. Only when all of the specified features are present can the screen be reliable and leak-proof, which together guarantees the achievement of the stated technical result—increased reliability of the impermeable screening effect. Failure to meet or omission of even one of the listed features increases the risk of screen leakage, which results in the failure to achieve the stated technical result.

Claims

1. An anti-seepage screen comprising a layer of bentomate, an intermediate layer of geotextile, a first layer of geomembrane, a first protective layer of geotextile, a drainage layer of 3D hydromat, a second layer of geomembrane and a second protective layer of geotextile, placed sequentially from bottom to top and fastened together at the edges.

2. An anti-seepage screen according to paragraph 1, characterized in that the thickness of the second layer of the geomembrane is greater than the thickness of the first layer of the geomembrane.

3. An anti-seepage screen according to paragraph 1, characterized in that control pipes are laid above the bentomate layer.

4. An anti-seepage screen according to paragraph 1, characterized in that the connection of the layers is made along the edges of the anti-seepage screen.

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