The construction process for a geomembrane installation involves several critical steps to ensure proper placement and functionality. Here’s an overview of the typical process:

1. Site Preparation
Survey and Design: The first step is to conduct a thorough site survey to assess the terrain, soil conditions, and other environmental factors. Based on this, a detailed design of the geomembrane system is created, specifying the type, thickness, and layout of the geomembrane.
Clearing and Grading: The site is cleared of vegetation, debris, and any obstacles that could damage the geomembrane. The ground is then graded to achieve the desired slope and smoothness, ensuring that the surface is free of sharp objects or irregularities.
2. Subgrade Preparation
Compaction: The subgrade, or the foundation layer, is compacted to provide a stable and even base for the geomembrane. Proper compaction is essential to prevent settlement and ensure the longevity of the liner.
Installation of Geotextile (if needed): A layer of geotextile fabric may be placed over the subgrade to provide additional protection against punctures and to enhance the overall stability of the geomembrane.
3. Geomembrane Placement
Unrolling the Geomembrane: The geomembrane is delivered to the site in large rolls. These rolls are carefully unrolled and laid out according to the design specifications. This process is usually done in sections to minimize handling and reduce the risk of damage.
Positioning: The geomembrane sheets are positioned with enough overlap between adjacent panels to allow for seaming. Care is taken to ensure that the membrane lies flat without wrinkles or folds.
4. Seaming and Welding
Overlap and Alignment: Adjacent geomembrane panels are overlapped according to the manufacturer’s guidelines, typically by 100 to 150 mm (4 to 6 inches). Proper alignment is crucial to ensure the integrity of the seam.
Welding: Seams between panels are welded using either thermal fusion or chemical bonding, depending on the material of the geomembrane. The most common method is thermal fusion, which involves heating the edges of the panels and pressing them together to form a continuous, impermeable seam.
Inspection of Seams: Each seam is inspected visually and often tested using non-destructive methods such as air pressure testing or vacuum testing to ensure a strong, leak-proof bond.
5. Quality Control and Testing
Visual Inspection: A thorough visual inspection of the entire installation is conducted to check for any visible defects, such as tears, punctures, or unbonded seams.
Testing: Additional tests, such as destructive testing of sample seams, may be performed to verify the quality of the welds. Any detected defects are repaired immediately.
6. Anchoring and Backfilling
Anchoring: The edges of the geomembrane are securely anchored in trenches or other designated anchor points around the perimeter of the site. This prevents the membrane from shifting or being displaced by wind, water, or other forces.
Backfilling: In some cases, a protective layer of soil or other material may be placed over the geomembrane to protect it from physical damage and UV exposure, particularly in applications where the liner will be exposed for extended periods.
7. Final Inspection and Documentation
Final Inspection: A comprehensive final inspection is conducted to ensure that the geomembrane installation meets all design specifications and quality standards.
Documentation: Detailed records of the installation, including test results, material certifications, and as-built drawings, are compiled and submitted as part of the project documentation.
8. Project Close-Out
Site Cleanup: Any remaining debris or unused materials are removed from the site.
Final Approval: The project is reviewed and approved by the relevant authorities or the client, marking the completion of the geomembrane installation.
This process ensures that the geomembrane liner is installed correctly, providing effective containment and environmental protection for its intended application.