不同埋管形式的预制能量管桩热响应试验研究

能量桩是通过在传统桩基础内安装换热管的新型节能减排技术。通过在PHC桩芯内埋设换热管形成预制能量管桩。现场采用单U和双U热响应试验,利用分布式光纤传感技术,对桩身的温度和应变分布进行了监测,得到了试验过程中能量桩的温度和应变变化规律;发现换热初期热量会堆积在能量桩内无法快速传递到桩外,整个过程桩体升温幅度不大,热量传递效率较低;揭示了预制能量管桩的热、力学变化特征,为预制能量管桩的优化设计和换热能力的评价提供了依据。

Thermal Response Tests on PHC Energy Piles with Different Configurationof Heat Exchange Loop

Energy pile is a new energy-saving and emission-reduction technology by installing heat exchange tubes in traditional pile foundations. In this paper, PHC energy piles were formed by embedding heat exchange tubes in the PHC piles. The single-U and double-U thermal response tests (TRT) were conducted. The distributed fiber optic sensing technology was used to monitor the temperature and strain distribution of the pile body, through which the temperature and strain changes of the energy pile were obtained during the TRTs. It was found that the energy in the initial stage of heating cannot be quickly transferred to the soil around the pile. Heat accumulated in backfilled sand in the hollow center of the energy pile. The temperature rise of the pile body was not obvious during the whole process, and the heat transfer was relatively inefficient. The TRTs reveal the thermal and mechanical changes of the PHC energy piles, which provide a basis for the optimized design of the PHC energy piles and the evaluation of performance of heat transfer.