Geotextiles (nonwoven/woven/filament/staple fiber) serve five major functions—filtration, drainage, isolation, reinforcement, and protection—and are essential materials for hydraulic embankments, road structures, municipal drainage, and ecological slope protection. This article clarifies selection logic, construction key points, and quality control to address common engineering issues such as piping, scouring, interlayer contamination, and inadequate drainage.

I. Core Functions and Design Principles

  • Filtration (soil retention with permeability): Follows four criteria—soil retention, permeability, clogging resistance, and durability—to prevent piping and seepage failure.
  • Isolation: Separates different media to prevent intermixing and failure of subgrade and cushion materials.
  • Drainage: Forms in-plane drainage channels to accelerate soil consolidation.
  • Protection: Covers and protects slopes, prevents scouring, and shields geomembranes from puncture.

II. Selection Criteria

  • Filament geotextile: High strength, anti-aging; preferred for hydraulic and high-speed rail projects, 300–800 g/m².
  • Staple fiber geotextile: Suitable for municipal, road, and general engineering projects; cost-effective, 200–600 g/m².
  • Woven geotextile: Used for reinforcement and temporary cofferdams; high tensile strength.

III. Construction and Quality Control

  • Lay flat without wrinkles; overlap ≥30–50 cm or use sewn connections. Strictly prohibit damage from sharp objects; cover with soil promptly and avoid prolonged UV exposure.
  • Incoming inspection: areal weight, tensile strength, elongation at break, equivalent opening size, and permeability coefficient.

IV. Typical Engineering Value

  • Embankment filtration: Eliminates piping and soil flow; phreatic line lowered by 0.5–1.0 m.
  • Road base: Isolates subgrade soil from aggregate, extending pavement life by over 30%.
  • Ecological slope protection: Combined with ecological bags/3D mats, improves soil stabilization and water retention, increasing vegetation survival rate by 60%.

With multi-functionality, low cost, and ease of installation, geotextiles have become the "building blocks" of geotechnical engineering. Proper selection and standardized installation significantly enhance structural safety and durability.