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Lianyi® Geomembrane is a kind of geosynthetic material with extremely low water permeability, mainly made of high-molecular polymers (such as plastics, rubber, etc.). Essentially, it is an artificial anti-seepage roll material, similar to a huge “plastic sheet”, but its performance, durability and engineering characteristics are far beyond those of ordinary plastic sheets.
Main Raw Materials and Types
According to the different polymer materials used, geomembranes are mainly classified into the following categories:
1.HDPE (High-density Polyethylene) geomembrane
*Features: Strong resistance to chemical corrosion, excellent UV aging resistance, high tensile strength, and a wide range of operating temperatures. It is currently the most widely used and largest in quantity type.
*Appearance: Usually black (with carbon black added to enhance anti-aging properties), and there are also other colors such as green, blue, etc.
*Applicable scenarios: Landfill sites, sewage treatment plants, tailings ponds, hazardous waste disposal sites and other projects with extremely high requirements for anti-seepage.
2.LLDPE (Linear low-density Polyethylene) geomembrane
*Features: Softer and more flexible than HDPE, better resistance to stress cracking, and stronger adaptability to uneven settlement.
*Applicable scenarios: Artificial lakes, landscape water systems, aquaculture, underground projects and other projects that require good deformation adaptability.
3.PVC (polyvinyl chloride) geomembrane
*Features: Good flexibility, easy to weld, and relatively low cost. However, it has poor UV resistance and usually requires the addition of plasticizers (there may be a problem of long-term migration aging).
*Applicable scenarios: Channel seepage prevention, reservoirs, temporary coverage, etc.
4.Other types: such as EPDM (Ethylene Propylene diene monomer rubber) geomembrane (with excellent cold resistance), CPE (chlorinated polyethylene) geomembrane , etc., are used in some special occasions.
*Anti-seepage and isolation: This is its most core function. It can effectively prevent the migration of liquids (water, sewage, chemical solutions) and gases, and at the same time separate two geosynthetic materials with different properties.
*Durability: High-quality geomembranes have excellent resistance to chemical corrosion, ultraviolet rays and aging, and their designed service life can reach over 50 years.
*High strength and elongation: It can withstand certain construction tensile stress and foundation settlement deformation during the service period.
*High cost-effectiveness: Compared with traditional clay anti-seepage layers, it has significant advantages such as thin thickness, light weight, fast construction speed, and saving land space and cost.
Geomembrane is an indispensable material in modern environmental geotechnical engineering and is widely used in
*Environmental protection project
*Landfill: As the anti-seepage layer for the base and roof, it prevents leachate from polluting the underground soil and water bodies.
*Anti-seepage for regulating tanks, anaerobic tanks and oxidation ponds in sewage treatment plants.
*Hazardous waste disposal site: Safely isolate harmful substances.
*Water conservancy projects
*Reservoirs, artificial lakes and rivers: Prevent water resource leakage.
*Channel: Anti-seepage of irrigation channels to enhance the efficiency of water resource utilization.
*Mining Engineering
*Tailings pond: Prevent tailings water containing heavy metals and other harmful substances from seeping into the ground.
*Municipal and Landscape Engineering
*Roof garden: Waterproof and root-proof.
*Landscape water pools and golf course ponds.
*Moisture-proofing and waterproofing for basements and tunnels.
*Aquaculture industry
*The bottom protection and seepage prevention of aquaculture ponds facilitate water level control and water quality management.
*Agriculture
*Anti-seepage for water storage cellars and irrigation water tanks.
Key Technical Points for Construction
The performance of geomembranes is highly dependent on correct construction. Key links include:
*Base layer treatment: The foundation must be level, compacted and smooth, free of tree roots, sharp stones and other sharp objects to prevent the geotextile membrane from being punctured.
*Laying: Carry out the laying when the weather is good, relax the laying to avoid stress concentration, and leave sufficient expansion and contraction allowance.
*Welding: This is the most crucial technology. The coils are joined into a single unit by using double-track hot melt welding (to form cavities for pressure detection) and extruded electrode welding (for detailed areas and repairs).
Detection
*Non-destructive testing: Conduct pneumatic testing (for double-track welding) or vacuum box testing (for extrusion welding) on all welds to check the sealing performance.
*Destructive testing: On-site weld seam samples are cut and sent to the laboratory for shear and peel strength tests.
*Protection: After laying is completed, a protective layer (such as geotextile, sand, etc.) should be covered in time to prevent direct sunlight and mechanical damage.
Common Misunderstandings and Precautions
It’s not the case that the thicker the better: The appropriate thickness (commonly 0.5mm – 3.0mm) and material of the geomembrane should be selected based on the engineering design requirements (such as water head pressure and foundation conditions).
The quality of materials is of vital importance: One should choose a brand with a good reputation and check its relevant certifications and test reports.
Professional construction is the key: “Three parts materials, seven parts construction.” It must be carried out by an experienced construction team with professional equipment; otherwise, even the best materials will not be able to play their role.
Summary
Geomembrane is a highly efficient and reliable new type of anti-seepage material, and it is a key technical product for solving problems such as environmental pollution control, water resource conservation, and infrastructure construction. Its successful application is a systematic project, which requires strict control over every link from material selection, design, construction to quality inspection.
Keyword：
1.Geomembrane