Experimental study of the frost heave mechanism of solar panel piled foundations in scaled centrifuge models

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4. Experimental study of the frost heave mechanism of solar panel piled foundations in scaled centrifuge models

The increasing demand for clean energy and the pursuit of more efficient systems have led to the establishment of solar panel fields in cold regions. However, prolonged periods with sub-zero temperatures may result in frost heave of the soil, which can in turn generate the uplift of deep foundations by frost jacking and compromise the functionality of the superstructure system. This work investigates the uplift mechanism induced by the frost-heaving phenomena on solar panel pile foundations, typically consisting of individual short driven steel piles, and explores possible mitigation interventions. Two centrifuge tests at an increased gravity of 20g and 30g were carried out in the geotechnical centrifuge of the Schofield Centre of the University of Cambridge (GEOLAB FROSPER project). They reproduced cold climate by freezing and thawing cycles on different reduced-scale models of solar panel foundations (single piles and connected pile groups). The samples consisted of a saturated clay-sand mixture susceptible to frost heave, comprising 80% Houston Sand and 20% Speswhite Kaolin. The monitoring data collected during the centrifuge tests, including temperatures and displacements of the surface of the soil and the head of the piles, revealed freezing of the shallowest layer of soils and heaving of both the ground and the piles.  The settlement of the piles on thawing was always smaller than the heave recorded on freezing, whereas the settlement of the soil surface during thawing was slightly larger than the original heave, resulting in a net uplift of the piles relative to the soil surface on a cycle of freezing and thawing.

5th European Conference on Physical Modelling in Geotechnics (ECPMG2024)

Energy geo-structures and climate effects