Field Based performance of Helical Piles Installed in High Expansive Clay-Video

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Video Summary

The presentation examines foundation challenges caused by expansive Yazoo clay in Mississippi. Traditional slab-on-grade foundations can crack as the soil swells and shrinks with moisture changes. Laboratory tests showed that repeated wetting and drying increases the soil’s void ratio and permeability, potentially allowing more water to enter. Researchers also found that Jackson-area soils tend to remain consistently wet, likely reflecting increased rainfall, making soil softness a concern.<br /><br />To explore a potentially more affordable alternative to deep foundations, the team tested helical piles of varying depths and configurations. They measured load capacity and monitored 25 piles over two years. Moisture sensors and field observations showed limited soil moisture variation, and pile movement was generally small, with the greatest reported displacement around one inch. Overall, the results suggest helical piles may perform well in Yazoo clay, though further work is needed to assess suitable pile depths, spacing, and cost for residential construction.

Keywords

Yazoo clay

foundation challenges

helical piles

slab-on-grade foundations

soil moisture

residential construction