Growing global energy demands have spurred significant interest in deep salt caverns as a promising energy storage solution. This study investigates the impact of temperature on the mechanical behavior and damage evolution of rock salt using primary creep-fatigue tests at various temperatures, coupled with real-time acoustic emission (AE) monitoring. The results show that elevated temperatures induce strain softening in the rock salt, leading to decreased deformation modulus and an increased unloading modulus. This softening leads to more pronounced primary creep and fatigue deformation. At low stress levels, increasing temperatures have a more pronounced effect on primary creep deformation. At high stress levels, the influence of temperature on fatigue deformation is relatively weaker, although elevated temperatures still result in more significant fatigue deformation. Compared to the b-value, the Ib-value exhibits greater sensitivity to microcrack development. Elevated temperatures also increase the disorder and complexity of AE events, leading to a marked decrease in natural time parameters (<InlineEquation ID="IEq1"> <EquationSource Format="TEX">${\kappa }_{1}$</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>κ</mi> <mn>1</mn> </msub> </math></EquationSource> </InlineEquation>, <InlineEquation ID="IEq2"> <EquationSource Format="TEX">$S$</EquationSource> <EquationSource Format="MATHML"><math> <mi>S</mi> </math></EquationSource> </InlineEquation>, and <InlineEquation ID="IEq3"> <EquationSource Format="TEX">${S}_{rev}$</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>S</mi> <mrow> <mi mathvariant="italic">rev</mi> </mrow> </msub> </math></EquationSource> </InlineEquation> values). Based on the RA–AF distribution, the proportions of tensile cracks at 20 °C, 40 °C, 60 °C, and 80 °C are 90.54%, 87.28%, 86.05%, and 83.77%, respectively. These results indicate that the ductility and plasticity of rock salt are enhanced at elevated temperatures. While tensile cracking remains the dominant mechanism at all tested temperatures, elevated temperatures promote the generation of shear cracks. These findings provide crucial insights for the design and safety assessment of salt cavern energy storage projects.

Fatigue Behavior of Rock Salt under Primary Creep Effect at Various Temperatures with Acoustic Emission Monitoring

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发表日期：

2025年7月8日

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Hang Li,
Hongling Ma,
Zhiwen Hu,
Zhen Zeng,
Jiangyu Fang,
Rui Liang,
Chunhe Yang

摘要

Growing global energy demands have spurred significant interest in deep salt caverns as a promising energy storage solution. This study investigates the impact of temperature on the mechanical behavior and damage evolution of rock salt using primary creep-fatigue tests at various temperatures, coupled with real-time acoustic emission (AE) monitoring. The results show that elevated temperatures induce strain softening in the rock salt, leading to decreased deformation modulus and an increased unloading modulus. This softening leads to more pronounced primary creep and fatigue deformation. At low stress levels, increasing temperatures have a more pronounced effect on primary creep deformation. At high stress levels, the influence of temperature on fatigue deformation is relatively weaker, although elevated temperatures still result in more significant fatigue deformation. Compared to the b-value, the Ib-value exhibits greater sensitivity to microcrack development. Elevated temperatures also increase the disorder and complexity of AE events, leading to a marked decrease in natural time parameters ( ${\kappa }_{1}$ $κ_{1}$ , $S$ $S$ , and ${S}_{rev}$ $S_{rev}$ values). Based on the RA–AF distribution, the proportions of tensile cracks at 20 °C, 40 °C, 60 °C, and 80 °C are 90.54%, 87.28%, 86.05%, and 83.77%, respectively. These results indicate that the ductility and plasticity of rock salt are enhanced at elevated temperatures. While tensile cracking remains the dominant mechanism at all tested temperatures, elevated temperatures promote the generation of shear cracks. These findings provide crucial insights for the design and safety assessment of salt cavern energy storage projects.