道面工程除冰能量桩系统作用机理与分析方法研究

Energy pile has dual function of bearing capacity and heat transfer capacity. In recent years, it has been gradually applied in the related engineering. However, the interaction mechanism of energy pile - soil under the flexible foundation is still unclear. This project aims to study the analytical method and interaction mechanism of energy pile - based pavement (such as, airport runway, freeway, etc.) de-icing system. New transparent soil material, which is suitable for THM multi-field coupling simulation, is developed. The mechanism and transmission process of energy among soil - energy pile - pavement is revealed. The temperature control geotechnical triaxial tests are carried out, the traditional soil thermal constitutive model is optimized, and the constitutive model for clay - pile interface considering heat - force coupling effect is established. Based on field test, the thermodynamic properties of energy pile, and the temperature effect to adjacent piles are measured. Numerical simulation model on energy pile-based pavement de-icing system considering THM multi-field coupling is established. The bearing capacity and safety performance of energy piles during the service period are discussed and anlyszed. The optimization design and effect evaluation of energy pile - based pavement de-icing system are carried out. Based on the load transfer method, the bearing capacity and settlement calculation method of the energy pile under the flexible foundation is bulit. The results can improve and innovate the interaction mechanism of energy pile - soil and the calculation theory on bearing capacity of energy pile under the flexible foundation. It also has important application values and economic benefits for the design and construction of energy pile.

能量桩兼具承担上部荷载和地源热泵传热器双重功能，近年来在工程领域中逐渐得到应用；但是，柔性基础下能量桩-土相互作用机理尚不明确。本项目拟针对机场跑道、高速公路等道面工程除冰能量桩系统作用机理与分析方法展开研究。研发适用于THM多场耦合分析的新型透明土材料，揭示土体-能量桩-道面能源传递过程与机理。开展温控土工三轴试验，优化黏性土热本构模型，建立考虑热-力耦合的黏性土-桩接触面本构模型。现场实测能量桩系统热力学特性及温度荷载对邻近桩基的影响，揭示能量桩-土荷载传递机理；建立道面工程除冰能量桩系统THM多场耦合数值计算模型，分析服役期内能量桩的承载与安全性能。开展道面工程除冰能量桩系统优化设计与效果评价；基于荷载传递法，建立柔性基础下能量桩承载力与沉降计算方法。研究成果将丰富并创新柔性基础下能量桩-土相互作用机理与能量桩承载力计算理论，对指导能量桩工程设计、施工具有重要的应用价值和经济效益。

围绕能量桩道面（桥面）工程除冰融雪技术，开展能量桩道面（桥面）工程除冰融雪系统作用机理与分析方法研究，系统分析了保道面（桥面）板保持零度以上温度（不结冰）的能源需求、能量桩的能源供给能力、以及上部荷载与温度联合作用下能量桩承载性能与安全性问题，阐明了循环温度对能量桩、道面（桥面）板的热致应力或变形问题，解决了能源需求与供给能力的计算问题。本项目相关成果，成功应用于江苏省江阴市市政桥梁、河南三门峡310国道公路桥梁等能量桩桥面除冰融雪工程应用中；有效解决冬季桥面积雪结冰对交通安全的问题，取得了显著的社会、经济及环保效益。依托本项目资助，获得了如下几点研究成果：.（1）研发了基于Teflon和碳纳米材料的新型透明土材料，基于透明土材料和图像处理技术，搭建了适用于本项目THM多场耦合分析的非嵌入式可视化试验装备与系统；结合现场实测数据，揭示了土体-能量桩-道面之间能源的传递与扩散过程。.（2）揭示了温度对土体热物性的影响机制，结合技术规范和本项目现场实测数据，建立了道面工程除冰融雪能源需求、能量桩能源供给能力的计算方法。.（3）基于温控直剪仪，测试温度作用下黏性土-桩接触面力学特性，揭示了土体材料中温度梯度、长期循环疲劳效应等因素对接触面强度的影响机制，并建立相应的应力-应变关系；建立了能量桩承载力与沉降理论计算方法。.依托本项目研究，发表标注本项目基金号（51778212）的学术论文32篇，其中SCI收录18篇、EI收录13篇；授权发明专利6项（其中中国发明专利4项，英国、澳大利亚国家发明专利2项），软件著作权登记1项；培养顺利毕业博士4名、硕士4名；部分研究成果已纳入行业标准《桩基地热能利用技术标准》（JGJ/T438-2018）中，立项编制中国工程建设标准化协会标准《能量桩桥面工程除冰融雪工程技术规程》。研究成果将丰富并创新了能量桩-土相互作用机理与能量桩承载力计算理论，对指导能量桩工程设计、施工具有重要的应用价值和经济效益。