Moisture migration in unsaturated sandy soil around energy pile and its mechanical consequences: a model test study
Moisture migration in unsaturated sandy soil around energy pile and its mechanical consequences: a model test study
The influence of heat extraction during winter operation of energy piles on soil moisture migration and pile bearing capacity in unsaturated soils has long been a frequently overlooked critical issue. This study conducted a model test to simulate the winter heating mode of an energy pile in unsaturated sandy soil, quantifying the effects of heat extraction via a U-tube pile on the resulting soil temperature field and concomitant moisture migration. After the temperature and moisture fields reached a relative steady state, a vertical load was employed to obtain the pile's load-settlement curve. Results revealed that soil cooling induced by heat extraction altered moisture distribution patterns, causing moisture to accumulate around the cooler pile body. This local increase in water content subsequently impaired the geotechnical bearing capacity, leading to an approximately 18% increase in the in settlement of energy pile. This research enhances the understanding of unsaturated soil behavior under thermal loads imposed by energy pile operation, emphasizing the necessity to account for thermally driven moisture redistribution and its mechanical consequences in energy geo-structure design. The findings provide experimental validation for the thermo-hydro-mechanical coupling mechanisms specific to heating scenarios, offering a foundation for optimizing sustainable energy geo-structures and refining numerical models.
Guohang Tang; Xianfeng Ma; Ben Ma; Yihan Hu; Haihua Zhang
11th International Conference on Physical Modelling in Geotechnics (ICPMG2026)
Session 5: Energy geo-structures and foundation systems
https://doi.org/10.53243/ICPMG2026-335