{"title":"Analysis of physical and mechanical properties of granite under different cooling methods under high temperatures thermal cycles","authors":"Haonan Li, Li Yu, Yue Wu, Weihao Wang, Xinyuan Zhang, Yongchuan Zhao","doi":"10.1144/qjegh2023-110","DOIUrl":null,"url":null,"abstract":"This study explores the impact of external pressure and high-temperature erosion on the physical and mechanical properties of granite, the geothermal well storage medium, during geothermal exploitation. Objectives include evaluating the effects of repeated heating and cooling cycles at different temperatures on porosity, permeability, and mechanical performance, with a focus on confining pressure's influence on permeability. Results indicate that under water-cooling and ambient conditions, porosity and permeability increase with cycle repetition, while compressive strength and elastic modulus decrease. Notably, Group B's (water-cooled) mechanical performance surpasses Group A (room temperature cooling) when porosity is below 1.5%. However, with increasing porosity due to thermal cycling, Group B's granite becomes inferior to Group A. CT scans reveal a post-cycling granite pore structure dominated by horizontal cracks, with primary uniaxial compression damage in the vertical direction. Thermal cycling reduces crack paths and load-bearing capacity, diminishing granite's mechanical performance. This study offers insights into subtle interactions between cooling methods and porosity during geothermal energy exploitation. It provides valuable guidance for optimizing geothermal energy use and mitigating potential adverse impacts on rock integrity, laying a foundation for further research and practical applications in geothermal energy exploitation.","PeriodicalId":20937,"journal":{"name":"Quarterly Journal of Engineering Geology and Hydrogeology","volume":null,"pages":null},"PeriodicalIF":1.3000,"publicationDate":"2024-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Quarterly Journal of Engineering Geology and Hydrogeology","FirstCategoryId":"89","ListUrlMain":"https://doi.org/10.1144/qjegh2023-110","RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"ENGINEERING, GEOLOGICAL","Score":null,"Total":0}
引用次数: 0
Abstract
This study explores the impact of external pressure and high-temperature erosion on the physical and mechanical properties of granite, the geothermal well storage medium, during geothermal exploitation. Objectives include evaluating the effects of repeated heating and cooling cycles at different temperatures on porosity, permeability, and mechanical performance, with a focus on confining pressure's influence on permeability. Results indicate that under water-cooling and ambient conditions, porosity and permeability increase with cycle repetition, while compressive strength and elastic modulus decrease. Notably, Group B's (water-cooled) mechanical performance surpasses Group A (room temperature cooling) when porosity is below 1.5%. However, with increasing porosity due to thermal cycling, Group B's granite becomes inferior to Group A. CT scans reveal a post-cycling granite pore structure dominated by horizontal cracks, with primary uniaxial compression damage in the vertical direction. Thermal cycling reduces crack paths and load-bearing capacity, diminishing granite's mechanical performance. This study offers insights into subtle interactions between cooling methods and porosity during geothermal energy exploitation. It provides valuable guidance for optimizing geothermal energy use and mitigating potential adverse impacts on rock integrity, laying a foundation for further research and practical applications in geothermal energy exploitation.
期刊介绍:
Quarterly Journal of Engineering Geology and Hydrogeology is owned by the Geological Society of London and published by the Geological Society Publishing House.
Quarterly Journal of Engineering Geology & Hydrogeology (QJEGH) is an established peer reviewed international journal featuring papers on geology as applied to civil engineering mining practice and water resources. Papers are invited from, and about, all areas of the world on engineering geology and hydrogeology topics. This includes but is not limited to: applied geophysics, engineering geomorphology, environmental geology, hydrogeology, groundwater quality, ground source heat, contaminated land, waste management, land use planning, geotechnics, rock mechanics, geomaterials and geological hazards.
The journal publishes the prestigious Glossop and Ineson lectures, research papers, case studies, review articles, technical notes, photographic features, thematic sets, discussion papers, editorial opinion and book reviews.