ISSN 0254-0096　CN 11-2082/K

• •

### 考虑桩土差异的能源桩传热模型及其热响应半径计算

1. 1. 广西大学土木建筑工程学院,南宁 530004;
2. 工程防灾与结构安全教育部重点实验室,南宁 530004;
3. 广西金属尾矿安全防控工程技术研究中心,南宁 530004
• 收稿日期:2021-03-22 出版日期:2022-10-28 发布日期:2023-04-28
• 通讯作者: 江 杰（1979——）,男,博士、研究员,主要从事环境岩土工程与建筑节能方面的研究。jie_jiang001@126.com
• 基金资助:
国家自然科学基金（52068004; 51978179; 51768006）; 广西重点研发项目（AC20238002）

### HEAT TRANSFER MODEL AND THERMAL RESPONSE RADIUS CALCULATION OF ENERGY PILE CONSIDERING PILE-SOIL DIFFERENCE

Ou Xiaoduo, Huang Zhongzheng, Qin Jinxi, Jiang Jie, Lyu Zhengfan

1. 1. School of Civil Engineering and Architecture, Guangxi University, Nanning 530004, China;
2. Key Laboratory of Disaster Prevention and Structural Safety of Ministry of Education, Guangxi University, Nanning 530004, China;
3. Guangxi Engineering Research Center for Metallic Tailings Security Prevention and Control, Nanning 530004, China
• Received:2021-03-22 Online:2022-10-28 Published:2023-04-28

Abstract: In order to solve the problem of error caused by treating pile and soil as the same medium in heat transfer analysis of energy pile, an unsteady heat transfer model of U-shaped buried pipe energy pile is established, which can consider the thermophysical properties difference between pile and soil. The accuracy of the model is verified by comparing with the linear heat source model. On this basis, the approximate simplified expression of thermal response radius of energy pile is obtained by series expansion. Finally, the heat exchange per unit pile length, the thermal diffusion coefficient, pile diameter and the soil type are analyzed, and the "heat storage ratio" is used to evaluate the influence of the above parameters on the heat transfer process of the energy pile. The results show that： compared with the linear heat source model, the model can describe the heat transfer process of energy pile more accurately, which can effectively avoid the problems of underestimating the excess temperature of pile wall in the initial stage of heat transfer and overestimating the pile temperature in the stable stage of heat transfer; in the typical operation cycle of energy pile, the error of the calculation method of thermal response radius proposed in this study is within 0.1 ℃, which meets the engineering requirements; during the heat transfer process of energy pile, the heat storage ratio of soil increases with the decrease of the heat capacity of pile and the relative difference of thermal diffusion coefficient between pile and soil; the excess temperature of pile wall and the heat storage ratio of soil decrease with the increase of pile diameter; with the increase of heat transfer time, the excess temperature difference of pile wall corresponding to different pile diameter increases gradually, and the difference of heat storage ratio of soil decreases gradually; under the same heat transfer power, the change rate of excess temperature of energy pile wall hardly changes with the increase of heat transfer time; after 90 days of heat transfer, the pile diameter has little effect on the distribution of energy transfer.