Microthermal Damage of Granite in Gonghe Basin, Qinghai Province

[Purposes] Granite is one of the main rock masses for geothermal energy storage in dry hot rocks. Studying the damage mechanism of granite caused by heat and thermal shock has certain engineering and theoretical significance for geothermal exploitation in dry hot rocks. [Methods] The entire process...

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Main Authors: XIE Jin, XI Baoping, HE Shuixin, LI Xiaoke, CAI Jiahao, JIA Peng
Format: Article
Language:English
Published: Editorial Office of Journal of Taiyuan University of Technology 2024-11-01
Series:Taiyuan Ligong Daxue xuebao
Subjects:
Online Access:https://tyutjournal.tyut.edu.cn/englishpaper/show-2345.html
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author XIE Jin
XI Baoping
HE Shuixin
LI Xiaoke
CAI Jiahao
JIA Peng
author_facet XIE Jin
XI Baoping
HE Shuixin
LI Xiaoke
CAI Jiahao
JIA Peng
author_sort XIE Jin
collection DOAJ
description [Purposes] Granite is one of the main rock masses for geothermal energy storage in dry hot rocks. Studying the damage mechanism of granite caused by heat and thermal shock has certain engineering and theoretical significance for geothermal exploitation in dry hot rocks. [Methods] The entire process of slowly raising granite from room temperature to 600 ℃, natural cooling in air or thermal shock cooling in water to room temperature was observed by using a polarizing microscope. The microscopic structures were analyzed by quantitatively analyzing the mineral area and the number of cracks in the field of view to investigate the damage effects on granite during the heating process and after thermal shock in different cooling media. [Findings] The results indicate that: 1) The mineral area of granite increases with temperature rise during the heating process. After natural cooling from high temperature, the mineral area is slightly larger than that before heat treatment, while after thermal shock in water, the mineral area is slightly smaller than that at 600 ℃ but significantly larger than that before the heat treatment.2) During the heating process, the overall trend of cracks in the field of view shows an increase in small cracks, followed by the formation of large cracks through the penetration of small cracks, and a continuous increase in both large and small cracks. The critical temperature for a decrease in small cracks and an increase in large cracks is around 300 ℃.3) After thermal shock in water, the total number of cracks in the high-temperature granite increases, with a significant increase in cracks between 0−100 μm. In contrast, after natural cooling in air, the total number of cracks in the granite decreases, and there is a significant decrease in cracks between 0−100 μm. This indicates that shorter and smaller cracks are more sensitive to cooling processes. 4) Through analyses of the mineral contraction degree and cracks amount changes, it is found that internal fracturing of high-temperature granite caused by thermal shock cooling in water is more severe.
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publisher Editorial Office of Journal of Taiyuan University of Technology
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spelling doaj-art-8db77f1903074a189f49128f8a8bd6a52025-08-20T01:54:12ZengEditorial Office of Journal of Taiyuan University of TechnologyTaiyuan Ligong Daxue xuebao1007-94322024-11-0155697198010.16355/j.tyut.1007-9432.202307011007-9432(2024)06-0971-10Microthermal Damage of Granite in Gonghe Basin, Qinghai ProvinceXIE Jin0XI Baoping1HE Shuixin2LI Xiaoke3CAI Jiahao4JIA Peng5College of Mining Engineering, Taiyuan University of Technology, Taiyuan 030024, ChinaCollege of Mining Engineering, Taiyuan University of Technology, Taiyuan 030024, ChinaCollege of Mining Engineering, Taiyuan University of Technology, Taiyuan 030024, ChinaCollege of Mining Engineering, Taiyuan University of Technology, Taiyuan 030024, ChinaCollege of Mining Engineering, Taiyuan University of Technology, Taiyuan 030024, ChinaCollege of Mining Engineering, Taiyuan University of Technology, Taiyuan 030024, China[Purposes] Granite is one of the main rock masses for geothermal energy storage in dry hot rocks. Studying the damage mechanism of granite caused by heat and thermal shock has certain engineering and theoretical significance for geothermal exploitation in dry hot rocks. [Methods] The entire process of slowly raising granite from room temperature to 600 ℃, natural cooling in air or thermal shock cooling in water to room temperature was observed by using a polarizing microscope. The microscopic structures were analyzed by quantitatively analyzing the mineral area and the number of cracks in the field of view to investigate the damage effects on granite during the heating process and after thermal shock in different cooling media. [Findings] The results indicate that: 1) The mineral area of granite increases with temperature rise during the heating process. After natural cooling from high temperature, the mineral area is slightly larger than that before heat treatment, while after thermal shock in water, the mineral area is slightly smaller than that at 600 ℃ but significantly larger than that before the heat treatment.2) During the heating process, the overall trend of cracks in the field of view shows an increase in small cracks, followed by the formation of large cracks through the penetration of small cracks, and a continuous increase in both large and small cracks. The critical temperature for a decrease in small cracks and an increase in large cracks is around 300 ℃.3) After thermal shock in water, the total number of cracks in the high-temperature granite increases, with a significant increase in cracks between 0−100 μm. In contrast, after natural cooling in air, the total number of cracks in the granite decreases, and there is a significant decrease in cracks between 0−100 μm. This indicates that shorter and smaller cracks are more sensitive to cooling processes. 4) Through analyses of the mineral contraction degree and cracks amount changes, it is found that internal fracturing of high-temperature granite caused by thermal shock cooling in water is more severe.https://tyutjournal.tyut.edu.cn/englishpaper/show-2345.htmlgranitehigh temperaturethermal shockmicrostructuredry hot rockgeothermal exploitation
spellingShingle XIE Jin
XI Baoping
HE Shuixin
LI Xiaoke
CAI Jiahao
JIA Peng
Microthermal Damage of Granite in Gonghe Basin, Qinghai Province
Taiyuan Ligong Daxue xuebao
granite
high temperature
thermal shock
microstructure
dry hot rock
geothermal exploitation
title Microthermal Damage of Granite in Gonghe Basin, Qinghai Province
title_full Microthermal Damage of Granite in Gonghe Basin, Qinghai Province
title_fullStr Microthermal Damage of Granite in Gonghe Basin, Qinghai Province
title_full_unstemmed Microthermal Damage of Granite in Gonghe Basin, Qinghai Province
title_short Microthermal Damage of Granite in Gonghe Basin, Qinghai Province
title_sort microthermal damage of granite in gonghe basin qinghai province
topic granite
high temperature
thermal shock
microstructure
dry hot rock
geothermal exploitation
url https://tyutjournal.tyut.edu.cn/englishpaper/show-2345.html
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AT xibaoping microthermaldamageofgraniteingonghebasinqinghaiprovince
AT heshuixin microthermaldamageofgraniteingonghebasinqinghaiprovince
AT lixiaoke microthermaldamageofgraniteingonghebasinqinghaiprovince
AT caijiahao microthermaldamageofgraniteingonghebasinqinghaiprovince
AT jiapeng microthermaldamageofgraniteingonghebasinqinghaiprovince