酸性化学溶液作用下花岗岩力学特性与参数损伤效应

Damage effect of granite's mechanical properties and parameters under the action of acidic solutions

以花岗岩为试验与研究对象,基于自然干燥状态以及不同流速、不同p H值的水化学溶液侵蚀作用,进行了一系列单轴压缩、三轴压缩及劈裂试验,对比分析了酸性水化学环境下花岗岩的强度损伤、变形特征及力学参数响应机制。试验结果表明:花岗岩的单轴、三轴抗压强度及抗拉强度、弹性模量与黏聚力随着酸性溶液p H值减小、循环水流速度增大而降低;泊松比则随着p H值减小、水流速度增大而增大;酸性溶液浸泡后花岗岩的内摩擦角较自然干燥状态有所降低,但较蒸馏水浸泡后花岗岩无明显变化;花岗岩的压缩变形特征有由脆性向延性转变的趋势。因此,自然水化学环境的p H值与流速是导致岩石变形特征改变及强度与力学参数损伤劣化的2个敏感性因素,而花岗岩对酸性溶液的p H值更为敏感。

Uniaxial compression tests,triaxial compression tests and splitting tests were conducted on the granite specimens after the erosion of chemical solutions with different p H values and different flow rates. The responses of strength damage,deformation behavior and mechanical parameters of granite in water and different acidic solutions were compared and analyzed. It shows that uniaxial and triaxial compressive strength,tensile strength,Young＇s modulus,and cohesion of granite decrease with the reduction of p H value or the increase of flow rate of acidic solutions,while Poisson＇s ratio is quite in reverse. The internal friction angle of granite after soaking in acidic solutions is smaller than granite in natural dry state,but there is no obvious change in comparison to granite soaking in water. Also,the compressive deformation of granite transforms from brittleness to ductility after soaking in acidic solutions. In conclusion,the p H value and flow rate of natural hydro-chemical environment are two factors that significantly change the strength damage,deformation behavior and mechanical parameters of rock. However,the p H value of acidic solution has a greater impact than the flow rate.