Long-term exposure to chemical solutions can change the mineral composition and microstructure and may seriously affect the physical and mechanical properties of rocks. Therefore, to clarify the effects of long-term exposure and types of acids on the mechanical properties of rocks, and to develop the constitutive model of acid-immersed rocks, uniaxial compression tests were carried out on acid-immersed sandstone specimens. The sample weakened, and the brittle failure behavior became more ductile by the acid immersion to the aqueous solution of hydrochloric or sulfuric acids. The duration of the compaction stage of the stress–strain curve increased, that of the elastic stage decreased; the peak stress, elastic modulus, and Poisson's ratio decreased, and the peak point strains increased with the acidity and the immersion duration. The brittle shear failure of the untreated specimen became more axial splitting type failure with acidity. The damage variable of the combined effects of chemical and stress was introduced, and a statistical damage model considering the compaction stage of the stress–strain curve was established based on the damage variable. The model well-simulated the experimentally obtained stress–strain curves of the acid-immersed specimens. Finite element models reflecting the characteristics of the acid-immersed sandstone were established based on CT images.

中文翻译：

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酸蚀砂岩单轴压缩力学性能

长期接触化学溶液会改变矿物成分和微观结构，并可能严重影响岩石的物理和机械性能。因此，为了阐明长期暴露和酸类型对岩石力学性质的影响，建立酸浸岩石本构模型，对酸浸砂岩试样进行了单轴压缩试验。通过酸浸到盐酸或硫酸的水溶液中，样品减弱，脆性破坏行为变得更具延展性。应力-应变曲线压实阶段持续时间增加，弹性阶段持续时间减少；峰值应力、弹性模量和泊松比降低，峰值点应变随着酸度和浸泡时间的增加而增加。未处理试样的脆性剪切破坏更趋向于酸度轴向劈裂型破坏。引入了化学和应力联合作用的损伤变量，并基于该损伤变量建立了考虑应力-应变曲线压实阶段的统计损伤模型。该模型很好地模拟了实验获得的酸浸试样的应力-应变曲线。基于CT图像建立反映酸浸砂岩特征的有限元模型。并基于损伤变量建立了考虑应力-应变曲线压实阶段的统计损伤模型。该模型很好地模拟了实验获得的酸浸试样的应力-应变曲线。基于CT图像建立反映酸浸砂岩特征的有限元模型。并基于损伤变量建立了考虑应力-应变曲线压实阶段的统计损伤模型。该模型很好地模拟了实验获得的酸浸试样的应力-应变曲线。基于CT图像建立反映酸浸砂岩特征的有限元模型。