In acidic environments, rock masses are frequently subjected to severe chemical corrosion, resulting in the initiation of numerous geological engineering disasters. This study aimed to collect physical and mechanical parameters of granite exposed to prolonged acid corrosion and analyze fracture characteristics using acoustic emission (AE) techniques. Additionally, it examined the evolution of pore structure and damage mechanisms through the use of low-field nuclear magnetic resonance (NMR) and fractal theory. The results demonstrate a monotonic decrease in mass, volume, density, P-wave velocity, and S-wave velocity of granite with increasing corrosion time. Particularly notable is the phased reduction observed in uniaxial compressive strength and elastic modulus. The transition from brittle to ductile failure in corroded granite is accompanied by a gradual decrease in internal fracture strength. The trend in the correlation dimension reveals the relationship between the formation time of the main fracture surface and the pore structure. Additionally, total porosity and macropores (D, Da) exhibit significant fractal characteristics. The fractal dimension correlates positively with the damage variable and inversely with uniaxial compressive strength and elastic modulus. This indicates that more severe pore structure damage leads to a higher fractal dimension and lower mechanical performance. Among these, Da demonstrates higher sensitivity in characterizing rock mechanical properties. These findings provide important basis for evaluating the stability of granite geotechnical engineering in acidic environments.

中文翻译：

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基于核磁共振技术的花岗岩力学性能及酸蚀损伤特征研究


在酸性环境下，岩体经常遭受严重的化学腐蚀，从而引发众多地质工程灾害。本研究旨在收集长期酸腐蚀花岗岩的物理和机械参数，并使用声发射（AE）技术分析断裂特征。此外，它还通过使用低场核磁共振（NMR）和分形理论研究了孔隙结构的演变和损伤机制。结果表明，随着腐蚀时间的增加，花岗岩的质量、体积、密度、纵波速度和横波速度单调减小。特别值得注意的是单轴抗压强度和弹性模量的阶段性降低。腐蚀花岗岩从脆性破坏到延性破坏的转变伴随着内部断裂强度的逐渐下降。相关维数的变化趋势揭示了主断裂面形成时间与孔隙结构之间的关系。此外，总孔隙率和大孔隙（D、Da）表现出显着的分形特征。分形维数与损伤变量正相关，与单轴抗压强度和弹性模量负相关。这表明更严重的孔隙结构破坏导致更高的分形维数和更低的力学性能。其中，Da 在表征岩石力学性质方面表现出较高的灵敏度。这些研究结果为评价花岗岩岩土工程在酸性环境下的稳定性提供了重要依据。