A new warehouse near the Autoroute 20 interchange needed to handle 50 kPa of floor load. The top 8 meters there are soft silty clay with intermittent peat lenses. Without treatment, total settlement would exceed 350 mm over five years. We designed a preloading with surcharge program using 4.5 m of granular fill placed over a sand drainage blanket. Vertical wick drains were installed on a 1.5 m triangular grid to accelerate primary consolidation. Piezometers and settlement plates tracked pore pressure dissipation weekly. The surcharge was removed once 95% of estimated primary consolidation was reached. That took 13 weeks instead of the 18 predicted without wick drains. The floor slab was then cast on the improved subgrade. For sites with similar conditions, combining this method with a densidad-cono-arena verification of fill compaction ensures uniform load transfer.
For Drummondville's soft clay, preloading with surcharge can cut settlement time by half compared to waiting for natural consolidation.