Nonwoven Geotextile Fabric Installation Guide

I. Pre-Construction Preparation

1. Material Specifications

• Select needle-punched/spunbond nonwoven geotextile fabric based on:
  • Filtration efficiency: Apparent Opening Size (AOS) ≤0.3mm (per ASTM D4751)
  • Permeability: ≥10⁻³ m/s flow rate (ASTM D4491)
  • Puncture resistance: ≥500N (ASTM D6241)

2. Site Preparation

• Remove all debris and rocks >30mm
• Compact subgrade to 85-90% Proctor density (lower than woven fabric requirements)

II. Installation Steps

1. Base Layer Preparation

• Use fine-grained sand (1-5mm) as cushion layer (thinner than woven applications)

2. Deployment Technique

• Unroll parallel to primary water flow direction (no directional strength concern)
• Allow 10-15% slack for soil conformity

3. Seaming Methods

MethodParametersOverlap300-500mm width (vs. 200mm for woven)Thermal Bond120-180°C (lower than woven fabrics)

4. Protection Layer

• Immediate coverage with ≤200mm granular material (thinner than woven)

III. Key Differentiators from Woven Geotextiles

1. UV Sensitivity: Maximum 24-hour exposure limit (vs. 48h for woven)
2. Seam Strength: 60% of parent material strength accepted (vs. 80% for woven)
3. Anchoring: No mechanical tensioning required

IV. Quality Control

• Conduct in-situ permeability tests (ASTM D4491) post-installation
• Monitor for clogging indicators:
  • 30% reduction in flow rate → Requires maintenance