Numerical Simulations of the Prethawing Performance of Lime-Energy-Column Embankments in Warm Permafrost Regions

Abstract

The thawing settlement of highway embankments remains an engineering challenges in permafrost regions. Lime-energy-columns (LECs) have the potential to constrain the total amount of such settlement by prethawing the warm permafrost. To better predict the performance of LEC foundations, a series of numerical calculation models were established to calculate their temperature characteristics during construction and operation. The numerical model was validated through LEC model tests and on-site monitoring data from permafrost highway embankments. The results showed that LECs can thaw the permafrost foundation completely and also heat the clay to resist refreezing during highway operation. The influences of peak LEC temperature, column spacing, and permafrost temperature were analyzed by adjusting the design parameters of the LEC embankment models. When the peak LEC temperature was 50°C, the column diameter 0.4 m, and the column spacing 1 m, the prethawing effect was excellent in warm permafrost regions, preventing the foundation from refreezing during 50 years of operation. However, when the temperature of the permafrost is low, the foundation would quickly refreeze. Therefore, LEC foundations are not applicable to cold permafrost regions.