The degradation of mechanical characteristics of sandstone, a common engineering material in acid environment, is directly related to the project service life forecast. In order to investigate the influence of water–rock interaction on the mechanical properties of red sandstone, a series of uniaxial and triaxial compression tests were conducted on sandstone immersed in solutions of different pH values and immersion times. Moreover, the effects of acid chemical corrosion on the microscopic structure of the sandstone were analyzed using scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS) tests. A chemical damage strength model was then formulated within the theoretical framework of chemical reaction kinetics theory. The results indicate that the different hydro-chemical solutions have a significant deterioration effect on the sandstone. In immersion tests, the water–rock reaction of sandstone is essentially completed after 30 days of immersion. With increasing immersion time, the uniaxial compressive strength of sandstone immersed in neutral and weakly acidic saline solutions shows an initial rapid decrease followed by a slow increase, while sandstone immersed in distilled water and strongly acidic solutions shows varying degrees of decrease over time. High confining pressure weakens the corrosion effect of the solutions on the sandstone, particularly, the neutral solution. In the triaxial compression tests, strong acid has a great corrosion effect on sandstone. The average peak strength of sandstone immersed in pH2, pH4, pH7, and distilled water decreased by 30.2%, 28.7%, 25.1%, and 22.8%, respectively. The model considers calcium precipitation not only reflects the change in pH value of the immersion solution with time but also effectively predicts the strength of sandstone immersed in different solutions. The results deepen our understanding of the deterioration mechanism of silicon-based porous rock under different chemical solutions and would be of importance for the long-term stability analysis of rock engineering in complex groundwater environments.

中文翻译：

---

水化学腐蚀对单轴和三轴压缩下红砂岩力学性能的影响


砂岩是酸性环境中常见的工程材料，其力学特性的退化与工程使用寿命预测直接相关。为了研究水-岩相互作用对红砂岩力学性能的影响，对浸泡在不同 pH 值和浸泡时间的砂岩溶液中进行了一系列单轴和三轴压缩试验。此外，使用扫描电子显微镜 （SEM） 和能量色散光谱仪 （EDS） 测试分析了酸化学腐蚀对砂岩微观结构的影响。然后在化学反应动力学理论的理论框架内制定了化学损伤强度模型。结果表明，不同的水化学溶液对砂岩具有显著的劣化作用。在浸泡试验中，砂岩的水-岩反应在浸泡 30 天后基本完成。随着浸泡时间的增加，砂岩浸入中性和弱酸性盐溶液中的单轴抗压强度最初呈快速下降后缓慢增加的趋势，而砂岩浸入蒸馏水和强酸性溶液中随时间呈不同程度的下降。高围压削弱了溶液对砂岩的腐蚀作用，尤其是中性溶液。在三轴压缩试验中，强酸对砂岩有很大的腐蚀作用。砂岩浸泡在 pH2、pH4、pH7 和蒸馏水中的平均峰强度分别降低了 30.2%、28.7%、25.1% 和 22.8%。 该模型认为钙沉淀不仅反映了浸泡溶液 pH 值随时间的变化，而且有效地预测了砂岩浸泡在不同溶液中的强度。研究结果加深了我们对硅基多孔岩石在不同化学溶液下劣化机理的理解，对复杂地下水环境下岩石工程的长期稳定性分析具有重要意义。