Cracking mechanism and acoustic emission characteristics of granite under varying thermal effects

Abstract Understanding the thermo-mechanical behavior of granite under high-temperature conditions is crucial for the safe and efficient development of deep geothermal resources. This study revealed the physico-mechanical properties, cracking mechanism and fracture precursor of granite via compressi...

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Main Authors: Yuan Cui, Chao Xu, Lei Xue, Fengchang Bu, Jun Zhu
Format: Article
Language:English
Published: Nature Portfolio 2025-08-01
Series:Scientific Reports
Subjects:
Online Access:https://doi.org/10.1038/s41598-025-14590-z
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author Yuan Cui
Chao Xu
Lei Xue
Fengchang Bu
Jun Zhu
author_facet Yuan Cui
Chao Xu
Lei Xue
Fengchang Bu
Jun Zhu
author_sort Yuan Cui
collection DOAJ
description Abstract Understanding the thermo-mechanical behavior of granite under high-temperature conditions is crucial for the safe and efficient development of deep geothermal resources. This study revealed the physico-mechanical properties, cracking mechanism and fracture precursor of granite via compression experiments with acoustic emission (AE) monitoring. Results indicated that 500 °C is the critical temperature for the brittle-ductile transition of granite, characterized by progressive degradation of P-wave velocity, Young’s modulus, and uniaxial compressive strength (UCS) with increasing temperature, while peak strain shows an inverse trend. As the temperature and number of thermal cycles increase, the physico-mechanical parameters, AE characteristics and the failure modes show a strong temperature dependence, whereby the temperature is categorized into “slight weakening range (25–200°C)”, “stable weakening range (200–500 °C)” and “significant weakening range (≥ 500 °C)”. Thermally induced cracks are mainly composed of extrusion cracks from mineral thermal expansion mismatch, and intergranular cracks along weakened grain boundaries. In addition, the high energy rate AE event can be regarded as the fracture precursor, but it is significantly affected by the thermal effect. This study aims to determine the optimal temperature, cooling method, and number of thermal cycles needed for geothermal resource extraction.
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spelling doaj-art-32512336314240abbd61fe3b6d5b9cf12025-08-20T03:43:11ZengNature PortfolioScientific Reports2045-23222025-08-0115111410.1038/s41598-025-14590-zCracking mechanism and acoustic emission characteristics of granite under varying thermal effectsYuan Cui0Chao Xu1Lei Xue2Fengchang Bu3Jun Zhu4State Key Laboratory of Lithospheric and Environmental Coevolution, Institute of Geology and Geophysics, Chinese Academy of SciencesCollege of Earth Science and Engineering, Shandong University of Science and TechnologyState Key Laboratory of Lithospheric and Environmental Coevolution, Institute of Geology and Geophysics, Chinese Academy of SciencesRisk-Group - ISTE - Institute of Earth Sciences, University of LausanneDepartment of Architecture and Civil Engineering, The City University of Hong KongAbstract Understanding the thermo-mechanical behavior of granite under high-temperature conditions is crucial for the safe and efficient development of deep geothermal resources. This study revealed the physico-mechanical properties, cracking mechanism and fracture precursor of granite via compression experiments with acoustic emission (AE) monitoring. Results indicated that 500 °C is the critical temperature for the brittle-ductile transition of granite, characterized by progressive degradation of P-wave velocity, Young’s modulus, and uniaxial compressive strength (UCS) with increasing temperature, while peak strain shows an inverse trend. As the temperature and number of thermal cycles increase, the physico-mechanical parameters, AE characteristics and the failure modes show a strong temperature dependence, whereby the temperature is categorized into “slight weakening range (25–200°C)”, “stable weakening range (200–500 °C)” and “significant weakening range (≥ 500 °C)”. Thermally induced cracks are mainly composed of extrusion cracks from mineral thermal expansion mismatch, and intergranular cracks along weakened grain boundaries. In addition, the high energy rate AE event can be regarded as the fracture precursor, but it is significantly affected by the thermal effect. This study aims to determine the optimal temperature, cooling method, and number of thermal cycles needed for geothermal resource extraction.https://doi.org/10.1038/s41598-025-14590-zHigh-temperature graniteCooling modeThermal cycleAcoustic emissionTemperature dependence
spellingShingle Yuan Cui
Chao Xu
Lei Xue
Fengchang Bu
Jun Zhu
Cracking mechanism and acoustic emission characteristics of granite under varying thermal effects
Scientific Reports
High-temperature granite
Cooling mode
Thermal cycle
Acoustic emission
Temperature dependence
title Cracking mechanism and acoustic emission characteristics of granite under varying thermal effects
title_full Cracking mechanism and acoustic emission characteristics of granite under varying thermal effects
title_fullStr Cracking mechanism and acoustic emission characteristics of granite under varying thermal effects
title_full_unstemmed Cracking mechanism and acoustic emission characteristics of granite under varying thermal effects
title_short Cracking mechanism and acoustic emission characteristics of granite under varying thermal effects
title_sort cracking mechanism and acoustic emission characteristics of granite under varying thermal effects
topic High-temperature granite
Cooling mode
Thermal cycle
Acoustic emission
Temperature dependence
url https://doi.org/10.1038/s41598-025-14590-z
work_keys_str_mv AT yuancui crackingmechanismandacousticemissioncharacteristicsofgraniteundervaryingthermaleffects
AT chaoxu crackingmechanismandacousticemissioncharacteristicsofgraniteundervaryingthermaleffects
AT leixue crackingmechanismandacousticemissioncharacteristicsofgraniteundervaryingthermaleffects
AT fengchangbu crackingmechanismandacousticemissioncharacteristicsofgraniteundervaryingthermaleffects
AT junzhu crackingmechanismandacousticemissioncharacteristicsofgraniteundervaryingthermaleffects