HDPE geomembrane has become the core anti-seepage material for tailing ponds, landfills, reservoirs, and chemical pools due to its low permeability coefficient, high tensile strength, and resistance to acid, alkali, and aging. This article establishes a full-process technical system covering material selection, base treatment, welding process, quality testing, and disease prevention to ensure long-term stability and zero-seepage performance of anti-seepage structures.

1. Material Selection and Specification Control

  • Thickness Standards: For municipal solid waste landfills, upper layer ≥2.0 mm, lower layer ≥1.0 mm; hazardous waste landfills ≥2.0 mm; hydraulic and aquaculture applications 0.5–1.5 mm; textured HDPE geomembrane is preferred for tailing pond slopes to increase the friction coefficient.
  • Key Performance Indicators: Permeability coefficient ≤1.0×10⁻¹² cm/s, oxidative induction time (OIT) ≥100 min, carbon black content 2%–3%, elongation at break ≥600%, UV and chemical resistance meeting a 50-year design life.

2. Base Treatment Technical Requirements

  • Remove sharp stones, tree roots, and debris; replace soft soil and compact to a compaction degree ≥95%.
  • Drainage slope ≥2%, with a smooth surface and no abrupt changes; horizontal welds are prohibited on slopes exceeding 30°.

3. Installation and Welding Process Key Points

  • Installation Sequence: Proceed from low to high elevation, with 1.5% excess reserved to accommodate settlement; avoid over-tensioning.
  • Overlapping and Welding: Double-track hot-melt weld overlap ≥80 mm; extrusion weld overlap ≥55 mm; welding temperature 180–200 °C; test welds must pass before batch construction; T-joints use parent material patches, and transverse welds must be offset by ≥500 mm.

4. Quality Testing and Acceptance

  • Air Pressure Testing: Inflate double-track welds to 0.15–0.20 MPa and hold for 5 minutes; pressure drop must remain within acceptable limits.
  • Spark/Vacuum Testing: Cover all nodes, repair areas, and pipe penetration points with a 100% pass rate.

5. Typical Defect Prevention

  • Incomplete or Missed Welds: Strengthen pre-job training and on-site process supervision.
  • Puncture Damage: Geotextile protective layer ≥400 g/m²; strictly control filler particle size.
  • Slope Sliding: Select textured geomembrane and optimize anchor trench dimensions and depth.

Through integrated control of material, design, construction, and testing, the HDPE geomembrane system can achieve a leachate containment rate of 99.99% with a service life of up to 50 years, making it the most economical and reliable anti-seepage solution for environmental protection and hydraulic engineering projects.