Effect of heat treatment on the shear fracture and acoustic emission properties of granite with thermal storage potential: A laboratory-scale test

IF 5 2区工程技术 Q1 ENGINEERING, MECHANICAL

Theoretical and Applied Fracture Mechanics Pub Date : 2024-08-15 DOI:10.1016/j.tafmec.2024.104621

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引用次数: 0

Abstract

The exploitation of geothermal resources enhances the energy structure but poses challenges related to thermal–mechanical issues. This study utilizes short core in compression (SCC) specimens of granite to investigate thermo-mechanical properties. We examined the effects of heat treatment temperature on physical properties, shear fracture toughness, as well as acoustic emission (AE) characteristics. Fracture surface morphology and microstructure of the heat-treated SCC specimens were also analyzed using 3D laser scanning and scanning electron microscopy. Results indicate that both mass loss and P-wave velocity decrease with increasing heating-treated temperature, and similar trends are observed in mechanical properties. Specifically, fracture energy and shear fracture toughness decline by 51.48 % and 61.27 %, respectively, as temperature rises from 25 °C to 750 °C. The b-value and proportion of shear cracks initially increase before falling, with an inflection point at 300 °C, linked to thermal-induced microstructural deterioration. Fractal dimension (D) and joint roughness coefficient (JRC) show significant increases with higher heat treatment temperatures. Microstructural degradation, including dehydration and thermal-induced microcracking, drives the reduction in shear properties of heat-treated granites. Overall, our findings offer valuable insights into determining various methods of heat storage reconstruction with great application potential.

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热处理对具有蓄热潜力的花岗岩的剪切断裂和声发射特性的影响：实验室规模试验

地热资源的开发利用改善了能源结构，但也带来了与热机械问题相关的挑战。本研究利用花岗岩的短芯压缩（SCC）试样来研究热机械性能。我们研究了热处理温度对物理特性、剪切断裂韧性以及声发射（AE）特性的影响。我们还使用三维激光扫描和扫描电子显微镜分析了热处理 SCC 试样的断裂表面形态和微观结构。结果表明，随着加热处理温度的升高，质量损失和 P 波速度都会降低，力学性能也有类似的趋势。具体来说，当温度从 25 °C 升至 750 °C 时，断裂能和剪切断裂韧性分别下降了 51.48 % 和 61.27 %。b 值和剪切裂纹的比例最初先增加后下降，在 300 °C 时出现拐点，这与热引起的微结构劣化有关。随着热处理温度的升高，分形尺寸（D）和接缝粗糙度系数（JRC）显著增加。微结构退化，包括脱水和热诱导微裂纹，是热处理花岗岩剪切性能降低的原因。总之，我们的研究结果为确定具有巨大应用潜力的各种蓄热重建方法提供了宝贵的见解。

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

Theoretical and Applied Fracture Mechanics 工程技术-工程：机械

CiteScore

8.40

自引率

18.90%

发文量

435

审稿时长

37 days

期刊介绍： Theoretical and Applied Fracture Mechanics'' aims & scopes have been re-designed to cover both the theoretical, applied, and numerical aspects associated with those cracking related phenomena taking place, at a micro-, meso-, and macroscopic level, in materials/components/structures of any kind. The journal aims to cover the cracking/mechanical behaviour of materials/components/structures in those situations involving both time-independent and time-dependent system of external forces/moments (such as, for instance, quasi-static, impulsive, impact, blasting, creep, contact, and fatigue loading). Since, under the above circumstances, the mechanical behaviour of cracked materials/components/structures is also affected by the environmental conditions, the journal would consider also those theoretical/experimental research works investigating the effect of external variables such as, for instance, the effect of corrosive environments as well as of high/low-temperature.