Abstract: Energy pile is a new technique which can save underground space and construction cost. However, the research focused on regarding the thermomechanical behavior between the pile and soil during heating and cooling are relative little. Based on the model test method, the experiment aims at systematically studying the thermomechanical behavior, heat transfer performance and bearing characteristics of four heat exchangers type piles including U-shaped (lashed and embedded types), W-shaped and Spiral-shape on saturated sand. The temperature of the pile and surrounding soil, the variation of tip resistance and horizontal soil pressure, and the pile head settlement are monitored. Meanwhile, the thermal strain of piles over time is also extrapolated. The results show that the pile temperature, thermal strain, pile head settlement and surrounding soil pressure related to W-shaped pile varies more obvious than Spiral-shape pile and single U-shaped pile.

Key words: energy pile, heat exchangers type, model test, thermal-mechanical behavior, saturated sand