不同埋管形式下能量桩热力学特性模型试验研究

桩埋管式地源热泵（也称能量桩）是一种可以节省地下空间和施工埋管费用的新技术，目前在国内外得到了一定的应用。然而，针对其在干砂中的传热特性和力学特性的研究却相对较少。基于模型试验方法，对不同埋管形式下，干砂中钢筋混凝土桩的传热特性及其力学特性进行了对比模型试验研究。试验测得桩体、桩周土体的温度变化规律，桩体应变和桩体热应力的变化规律，并对比分析了温度影响下基桩的极限承载力。试验研究结果表明，同样输入功率条件下，不同埋管形式相比，W型和螺旋型桩的应力变化和桩顶沉降量均较单U型桩要大。

MODEL TESTS ON THERMAL MECHANICAL BEHAVIOR OF ENERGY PILES INFLUENCED WITH HEAT EXCHANGERS TYPES

Pile geothermal heat pump system (also called energy pile) is a new heat pump system that can save underground space and construction cost, which to date has been used at home and abroad. However, the studies focusing on the heat transfer efficiency and mechanical characteristics of piles in dry sand are still limited. Based on the model test, the heat transfer performance and mechanical characteristics of different heat exchange concrete piles in dry sand are investigated. The temperature of pile and soil around pile, the thermal strain and thermal stress of the piles induced by temperature variation are measured. Moreover, the ultimate bearing capacity of the piles associated with different temperatures is analyzed. The results show that, for different types of heat exchangers under the same power of pump, the strain variation and pile head settlement of the W-shaped and S-shaped piles are more significant than that of the single U-shaped pile.