Construction of Composite Drainage Nets in Highway Projects

Key Advantages in Highway Construction

1. High Drainage Capacity – Rapidly removes water from the subgrade, reducing pore water pressure and preventing weakening of the road structure.

2. Soil Separation & Stabilization – Prevents fine soil particles from clogging the drainage system while reinforcing weak subgrades.

3. Reduces Frost Heave & Pavement Damage – Minimizes water retention, lowering the risk of freeze-thaw damage in cold climates.

4. Cost & Time Efficiency – Faster installation compared to traditional drainage systems, reducing labor and material costs.

5. Long-Term Durability – Resists chemical degradation and maintains performance over decades.

Construction Steps

1. Site Preparation

• Excavate and level the subgrade to design specifications.

• Remove debris, sharp objects, and unstable soil to prevent damage to the drainage net.

2. Subgrade Treatment (If Needed)

• Compact weak or loose subsoil to improve load-bearing capacity.

• Apply a geotextile separator (if required) to prevent fine soil migration into the drainage layer.

3. Installation of Composite Drainage Net

• Roll out the drainage net horizontally over the prepared subgrade.

• Ensure proper overlap (typically 30–50 cm) and secure edges with stakes or adhesive to prevent shifting.

• Connect the net to outlet pipes or edge drains for proper water discharge.

4. Backfilling & Compaction

• Cover the drainage net with a permeable granular fill (e.g., gravel or crushed stone).

• Compact the fill layer in thin lifts to avoid damaging the geocomposite.

5. Pavement Construction

• Proceed with standard road base, asphalt, or concrete layers as per design.

Applications in Highways

• Subsurface Drainage – Prevents waterlogging under pavements.

• Retaining Walls & Embankments – Reduces hydrostatic pressure behind structures.

• Tunnel & Bridge Approaches – Controls groundwater seepage.

• Landfill & Railway Projects – Used for similar drainage purposes.

Maintenance Considerations

• Inspect outlet pipes periodically to ensure no clogging.

• Check for soil settlement or damage after heavy rainfall.

By using composite drainage nets, highway projects achieve better longevity, reduced maintenance, and improved performance in wet conditions.