Centrifuge modelling of laterally loaded piles in dense sand under varying saturation conditions

This study investigates the response of short piles to lateral loads in partially saturated soils, as often occurs in solar panel foundations which are exposed to wind action. In such cases, owing to their limited length, the piles transfer the external loads to the shallow soil layer, which is often partially saturated and therefore exhibits additional strength due to pore suction. The influence of partial saturation on pile behaviour is examined in this work through centrifuge tests on a homogeneous Hostun sand model with varying groundwater table depths. The experimental programme also includes in-flight cone penetration tests to assess soil strength profiles under different saturation conditions. Results show that pile resistance is higher in partially saturated than in fully saturated or dry conditions, consistent with the larger strength profiles measured by the cone penetration tests. These experimental trends are also captured by an analytical pile model accounting for suction-induced strength enhancement in unsaturated soils. Experimental variability arising from minor differences in density or load eccentricity is found to have a marginal influence on measurements. These findings highlight the importance of accounting for partial saturation to improve the reliability and cost-effectiveness of the design of short piles subjected to lateral loads.