本文针对大直径桥梁能量桩的传热特性，通过开展现场试验测试了大直径桥梁能量桩的热交换率和桩土温度场的分布。同时建立大直径桥梁能量桩三维数值模型，通过将现场实测数据与数值模拟结果对比，验证了建立模型的合理性。基于验证的模型开展了参数敏感性分析，探究了桥墩与周围空气的对流换热对大直径能量桩传热特性的影响机制。研究表明，大直径桥梁能量桩的热交换率可达-222.28 W/m，约为常规能量桩的1.5~3.9倍，但较大的直径也导致了横截面上桩体温度的不均匀分布，换热管附近的桩体温度明显升高，比中轴线位置处的桩体温度高约3 ℃；当气温较低时，桥墩与周围空气的对流换热会造成桥墩温度的下降，这会提高桥梁能量桩夏季工况中的热交换率；当桥墩表面由自然对流（空气流速0 m/s）变为强制对流（空气流速5 m/s）时，桥梁能量桩的热交换率提高约22 W/m。

This study focuses on investigating the heat transfer characteristics of large-diameter bridge energy piles through field tests, aiming to examine the heat exchange rate and temperature distribution of a full-scale large-diameter bridge energy pile and surrounding soil. Additionally, three-dimensional numerical models of large-diameter bridge energy pile are developed and validated by comparing field measurements with simulation results. With the validated model, a parameter sensitivity analysis is conducted to explore the influence mechanism of convective heat exchange between bridge piers and surrounding air on the heat transfer characteristics of large-diameter energy pile. The results indicate that the heat exchange rate of large-diameter bridge energy pile can reach -222.28 W/m, which is approximately 1.5 to 3.9 times higher than that of conventional energy piles. However, the larger diameter of the pile leads to uneven temperature distribution across the cross section. Specifically, the temperature near the heat exchange tubes is significantly higher (around 3℃) compared to the temperature at the central axis position. Furthermore, it is observed that in low-temperature conditions, the convective heat exchange between bridge piers and surrounding air causes a decrease in the temperature of the pier, thereby increasing the heat exchange rate of the bridge energy pile under summer mode. When the surface of the pier transitions from natural convection (air flow rate of 0 m/s) to forced convection (air flow rate of 5 m/s), the heat exchange rate of the bridge energy pile increases by approximately 22 W/m.

TU473