Predicting Pile Setup (Freeze): A New Approach Considering Soil Aging and Pore Pressure Dissipation

Pile setup or freeze is the phenomenon of the increase of pile capacity over time during and after the dissipation of pore pressure and the stabilization of lateral earth pressure. Driven piles regain capacity after installation because of the excessive pore pressure dissipation and soil aging, which causes increase in the drained friction angle on pile shaft. This study is designed to determine the mechanism of the soil aging effect on pile setup and to provide engineers a simple, rational, and accurate model for predicting the capacity of piles over time by reviewing, analyzing and investigating collected full-size pile load testing data. Soil aging effect on pile setup, specifically on the growth of the drained friction angle on pile wall, is investigated and formulated by accounting for the factors of over-consolidation ratio (OCR) and lateral earth pressure, etc. A mechanistically-determined prediction model for pile setup by considering the effect of pore pressure dissipation and soil aging is established. The deterministic model is verified with measured pile capacities collected from the existing static load and dynamic test data. A final analysis is performed detailing the accuracy of the developed prediction model compared with the existing statistics-based prediction models.