The Challenge
Reclaiming land from the Lekki lagoon margin required containment of dredged fill and prevention of saline water ingress into newly formed land parcels, on a site with continuous tidal movement and soft alluvial mud.
Our Solution
Willem Olaf supplied 1.5 mm HDPE geomembrane as a containment liner along the bund walls and cell floors, welded on site by wedge and extrusion methods, with a non-woven geotextile cushion layer protecting the liner from the underlying mud and any debris in the dredged fill.
The Outcome
Over 40 hectares of reclaimed land were lined and contained within a single dry-season programme, with zero reported liner failures during the first full rainy season after handover.
The Challenge
A 22 km section of the Kaduna–Abuja corridor had failed repeatedly because of a weak lateritic subgrade that pumped fines into the sub-base during the rainy season, causing rutting and pothole formation within months of resurfacing.
Our Solution
A woven geotextile separation layer was laid across the full carriageway width to stop fines migrating into the imported sub-base, with a biaxial geogrid placed directly above to reinforce the sub-base and distribute axle loads across the weak subgrade.
The Outcome
Sub-base thickness was reduced by 150 mm against the original design, cutting aggregate haulage by an estimated 9,000 m³ across the section, and the rehabilitated section has carried two full rainy seasons without rutting.
The Challenge
An active gully head in Anambra State was advancing toward farmland and a feeder road, driven by concentrated stormwater runoff cutting through unstable, sandy lateritic soil during the rainy season.
Our Solution
Triaxial geogrid reinforcement was installed across the regraded slope faces to stabilise the soil mass, with woven geotextile placed beneath topsoil to support vegetation establishment and a geogrid-reinforced channel lining built to direct stormwater flow away from the gully head.
The Outcome
Gully head advance was halted within the first rainy season after installation, and vegetation cover across the reinforced slopes reached over 80% within 12 months, removing the need for ongoing mechanical repair.
