关键词: 循环温度, PHC能量桩, 现场试验, 热力响应, 承载性能

Abstract: Energy pile is a new building energy-saving technology, which has both functions of the bearing performance and the ground source heat pump heat exchanger. Based on the pile foundation engineering project of Zhoukou Normal University gymnasium in Henan province, field tests on the thermo-mechanical response and bearing capacity of PHC energy pile under cooling-heating cyclic temperature are carried out. The temperature and the strain of PHC energy pile are measured. The temperature-induced stress, side resistance, and heat exchange performance are analyzed and discussed. Test results show that: the distribution of the temperature-induced stress along pile depth varies greatly under cooling-heating cyclic temperature in this study. There is some negative shaft friction resistance developed in the upper part of the pile. The multiple relationship between the maximum thermal stress and temperature difference is 212 or 115 under summer or winter mode. Finally, a calculation formula of pile-soil friction coefficient considering temperature effect is proposed. Using this formula, the calculation method of bearing capacity of PHC energy pile is modified. The calculation results are in good agreement with field test results.

Key words: cyclic temperature, PHC energy pile, filed test, thermo-mechanical response, bearing capacity