循环温度下能源桩土热传导解析计算模型研究

Study on Analytical Calculation Model of Energy Pile-Soil Heat Conduction under Cyclic Thermal

在实际工程中能源桩与周围的热传递作用是一个长期多次循环的过程。依托能源桩土热传导离心机模型试验结果,基于有限长热源模型,对长期冷热循环温度作用下能源桩桩周土体温度场进行了理论计算,并将所得解析解与室内试验桩周土体温度实测值进行了对比分析,结果表明:有限长线热源模型相较于无限长线热源模型精度更高,且无论是冷循环还是热循环,在循环后期延米换热功率都存在一定程度的降低,冷效率的降低相较于热效率更为显著,降幅可达13.15%;桩周土温在桩身中段范围呈现较为稳定的态势,而桩端由于竖向传热的影响,桩端土体变温区间显著收缩;在同一时刻处,能源桩传热效率随着距桩中心距离增大而逐渐减小。

In practical engineering,the heat transfer between energy piles and surrounding soil is a long-term and repeated cycle process.Based on the results of centrifuge model test and the finite line source model,the temperature of soil around pile under cyclic thermal effection is theoretically calculated.The analytical solutions are compared with the measured value of soil temperature of the test.The results show that the finite line source model has higher accuracy than the infinite line source model.In addition,the heat transfer power of the meters decreased to a certain extent at the later stage of both cold and thermal cycles,and the reduction of cold efficiency is more significant than that of thermal efficiency and it can be reduced by up to 13.15%.The soil temperature around the pile showed a relatively stable trend in the middle section of the pile body,while the variable temperature range of the soil at the pile end shrank significantly due to the influence of vertical heat transfer.With the increase of the distance from the center of the pile,at the same time,the heat transfer efficiency of the energy pile gradually decreases.