Soil Structure Interaction in Geothermal Foundations

地热基础中土壤结构的相互作用

• 批准号: 0928159
• 负责人: John McCartney
• 金额: $ 49.51万
• 依托单位: University of Colorado at Boulder
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-08-01 至 2012-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0928159&HistoricalAwards=false
• 关键词: Soil; Structure; Interaction; Geothermal; Foundations

This award is funded under the American Recovery and Reinvestment Act of 2009(Public Law 111-5).The U.S. is currently pursuing technologies to improve the energy efficiency of buildings. One approach, which is the focus of this research, involves embedding geothermal heat exchange systems within deep foundations to gain improved energy efficiency of building heat pumps. Despite the potential cost savings gained through the combined use of equipment and construction materials for both the foundation support and heating/cooling systems, this approach is not without risk. The thermal interaction between the inhabited part of a building and its subsurface structural components may lead to both geotechnical and building system concerns. For example, drawing excessive amounts of heat from geothermal foundations may lead to ground freezing and potential surface heave, cyclic expansion and contraction of foundation materials due to rapid fluctuations in heat pump temperatures may lead to changes in side friction, and non-sustainable heat exchange patterns can lead to a reduction in heat exchange efficiency between the building and ground over time. A research approach involving numerical simulations of the thermal, hydraulic, and mechanical interaction between geothermal foundations and surrounding soils is being used to better characterize these risks. The parameters for these simulations are being determined using novel true-triaxial tests with temperature and hydraulic control, and the results from the simulations are being validated against a series of centrifuge modeling experiments on geothermal foundations under different temperature and loading conditions. The validated simulation tool will be used to provide practical design guidance to engineers to aid in defining the appropriate heat exchanger geometric configuration, foundation size and spacing, and building heat pump control conditions to gain both optimal heat exchange and foundation performance for a given soil profile. Interaction with industry partners (ADSC) will aid in the transfer of research findings to practicing engineers and foundation contractors. This study is being used to augment education at the CU Boulder through integration of topics from soil mechanics, building heating systems, physical modeling and constitutive modeling; which will provide new opportunities for broad-based training to students entering this new field. Under-represented students will be recruited through cooperation with established diversity initiatives at CU Boulder, as these populations are particularly missing from the foundation engineering community.

该奖项是根据2009年美国复苏和再投资法案（公法111-5）资助的。美国目前正在寻求提高建筑物能源效率的技术。 一种方法，这是本研究的重点，涉及嵌入地热热交换系统深基础，以提高建筑热泵的能源效率。 尽管通过将设备和建筑材料结合用于基础支撑和加热/冷却系统可以节省成本，但这种方法并非没有风险。 建筑物的居住部分与其地下结构部件之间的热相互作用可能导致岩土工程和建筑系统的问题。 例如，从地热基础吸取过量的热量可能导致地面冻结和潜在的表面隆起，由于热泵温度的快速波动导致的基础材料的周期性膨胀和收缩可能导致侧摩擦的变化，并且不可持续的热交换模式可能导致建筑物与地面之间的热交换效率随着时间的推移而降低。 一种研究方法，涉及地热基础和周围土壤之间的热，水力和机械相互作用的数值模拟正在被用来更好地描述这些风险。 这些模拟的参数正在确定使用新的真三轴试验与温度和液压控制，并从模拟的结果进行验证对一系列离心模型实验在不同的温度和载荷条件下的地热基础。 经过验证的模拟工具将用于为工程师提供实用的设计指导，以帮助定义适当的热交换器几何配置，基础尺寸和间距，以及建筑热泵控制条件，以获得给定土壤剖面的最佳热交换和基础性能。 与行业合作伙伴（ADSC）的互动将有助于将研究成果转移给执业工程师和基础承包商。 这项研究被用来通过整合土壤力学，建筑供暖系统，物理建模和本构建模等主题来增强CU Boulder的教育;这将为进入这一新领域的学生提供广泛培训的新机会。 代表性不足的学生将通过与CU Boulder既定的多样性计划合作来招募，因为这些人口在基础工程社区中特别缺乏。