Deterioration of equivalent thermal conductivity of granite subjected to heating-cooling treatment

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外文摘要：Understanding the thermal conductivity of granite is critical for many geological and deep engineering applications.The heated granite was subjected to air-,water-,and liquid nitrogen(LN2-)coolings in this context.The transient hot-wire technique was used to determine the equivalent thermal conductivity(ETC)of the granite before and after treatment.The deterioration mechanism of ETC is analyzed from the meso-perspective.Finally,the numerical model is used to quantitatively study the impact of cooling rate on the microcrack propagation and heat conduction characteristics of granite.The results show that the ETC of granite is not only related to the heating temperature,but also affected by the cooling rate.The ETC of granite decreases nonlinearly with increasing heating temperature.A faster cooling rate causes a greater decrease in ETC at the same heating temperature.The higher the heating temperature,the stronger the influence of cooling rate on ETC.The main explanation for the decrease in ETC of granite is the increase in porosity and microcrack density produced by the formation and propagation of pore structure and microcracks during heating and cooling.Further analysis displays that the damage of granite at the heating stage is induced by the difference in thermal expansion and elastic properties of mineral particles.At the cooling stage,the faster cooling rate causes a higher temperature gradient,which in turn produces greater thermal stress.As a result,it not only causes new cracks in the granite,but also aggravates the damage at the heating stage,which induces a further decrease in the heat conduction performance of granite,and this scenario is more obvious at higher temperatures.

外文关键词：

Equivalent thermal conductivity(ETC)GraniteHeating-cooling treatmentPore structureMicrocrackGrain-based model

作者：

Mohua Bu、Peng Zhang、Pingye Guo、Jiamin Wang、Zhaolong Luan、Xin Jin

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作者单位：

State Key Laboratory for Geo-Mechanics and Deep Underground Engineering,China University of Mining and Technology(Beijing),Beijing,100083,China

School of Mechanics and Civil Engineering,China University of Mining and Technology(Beijing),Beijing,100083,China

School of Qilu Transportation,Shandong University,Jinan,250001,China

Academy of Deep Earth Sciences,Chinese Institute of Coal Science,Beijing,100013,China

China State Key Laboratory of Coal Mining and Clean Utilization,China Coal Technology and Engineering Group,Beijing,100013,China

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基金：

Natural Science Foundation of ChinaNatural Science Foundation of ChinaGeneral Projects for Scientific and Technological Innovation of China Coal Science and Industry Group

项目编号：

42241145419410182022-MS001

出版年：

2024

DOI：

10.1016/j.jrmge.2023.11.014

岩石力学与岩土工程学报(英文版)

中国科学院武汉岩土力学所中国岩石力学与工程学会武汉大学

岩石力学与岩土工程学报(英文版)

CSTPCD

影响因子：0.404

ISSN：1674-7755

年,卷(期)：2024.16(10)