Thermo-mechanical behavior of an energy retaining pile for geothermal extraction

IF 3.3 2区工程技术 Q3 ENERGY & FUELS

Geomechanics for Energy and the Environment Pub Date : 2024-08-31 DOI:10.1016/j.gete.2024.100587

Di Wu , Liang Kong , Gangqiang Kong , Jincheng Fang , Chenglong Wang , Yifei Wang

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引用次数: 0

Abstract

A field test was conducted to assess the thermo-mechanical behavior of a full-scale energy retaining pile (ERP) adjacent to a utility tunnel during geothermal extraction. Numerical models were also established and calibrated using measured data. The extracted thermal power, temperature, thermally induced strain and stress, and bending moment of the ERP were analyzed. Additionally, a comparative analysis was conducted using validated numerical models to assess the impact of the air temperature (T_air) inside the adjacent utility tunnel on the thermo-mechanical behavior of the ERP. The findings highlight that the extraction thermal power of the tested ERP was 57 W/m, with the short-term geothermal extraction operation yielding even higher values of 200–250 W/m. The operation of the adjacent high-temperature utility tunnel can lead to an average increase of approximately 15 % in the extracted thermal power of the ERP. Additionally, during the geothermal extraction, regardless of the value of T_air, the ERP primarily reflected in changes to the axial thermo-mechanical behavior. However, the higher-temperature utility tunnel can result in a notable bending moment of the ERP prior to the geothermal extraction operation. Thus, considering the influence of T_air on the thermo-mechanical behavior of the ERP becomes crucial during the preliminary design phase.

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用于提取地热的能量保留桩的热力学行为

我们进行了一次实地测试，以评估地热开采期间邻近公用事业隧道的全尺寸能量保留桩（ERP）的热机械行为。此外，还利用测量数据建立并校准了数值模型。对提取的热功率、温度、热诱导应变和应力以及 ERP 的弯矩进行了分析。此外，还使用经过验证的数值模型进行了对比分析，以评估邻近公用事业隧道内的空气温度（Tair）对 ERP 热机械行为的影响。研究结果表明，经测试的 ERP 的提取热功率为 57 W/m，短期地热提取操作产生的数值甚至更高，达到 200-250 W/m。相邻高温公用隧道的运行可使企业资源规划系统的提取热功率平均提高约 15%。此外，在地热提取过程中，无论 Tair 值如何，ERP 主要反映在轴向热机械行为的变化上。然而，在地热提取操作之前，较高温度的公用事业隧道会导致 ERP 产生明显的弯矩。因此，在初步设计阶段，考虑 Tair 对 ERP 热机械行为的影响至关重要。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Geomechanics for Energy and the Environment Earth and Planetary Sciences-Geotechnical Engineering and Engineering Geology

CiteScore

5.90

自引率

11.80%

发文量

期刊介绍： The aim of the Journal is to publish research results of the highest quality and of lasting importance on the subject of geomechanics, with the focus on applications to geological energy production and storage, and the interaction of soils and rocks with the natural and engineered environment. Special attention is given to concepts and developments of new energy geotechnologies that comprise intrinsic mechanisms protecting the environment against a potential engineering induced damage, hence warranting sustainable usage of energy resources. The scope of the journal is broad, including fundamental concepts in geomechanics and mechanics of porous media, the experiments and analysis of novel phenomena and applications. Of special interest are issues resulting from coupling of particular physics, chemistry and biology of external forcings, as well as of pore fluid/gas and minerals to the solid mechanics of the medium skeleton and pore fluid mechanics. The multi-scale and inter-scale interactions between the phenomena and the behavior representations are also of particular interest. Contributions to general theoretical approach to these issues, but of potential reference to geomechanics in its context of energy and the environment are also most welcome.