离子侵蚀下注浆结石体劣化机理分析

针对水泥-水玻璃注浆结石体（C-S结石体）在离子侵蚀环境下劣化机理研究较少之问题，通过无侧限抗压强度试验，分析了C-S结石体在3种不同浓度的硫酸盐、氯盐及二者混合液侵蚀后，不同龄期条件下的宏观力学性能变化规律；采用SEM、EDS和XRD相结合的方法观察C-S结石体细观结构及化学成分变化，揭示C-S结石体离子侵蚀损伤机理。研究结果表明：（1）侵蚀时间少于28 d时，离子溶液对C-S结石体强度增长并未产生明显影响；（2）侵蚀时间28 d到90 d时，高浓度离子溶液中C-S结石体劣化显著，${rm{ SO}}_4^{2-} $离子溶液浓度20 g/L时，C-S结石体90 d强度值仅为28 d强度值的2.43%；（3）C-S结石体受离子侵蚀后，Ca2+离子析出，破坏了内部的溶解动态平衡，导致其内部发生改变，无侧限抗压强度大幅度折减；（4）C-S结石体受离子侵蚀影响主要以${rm{ SO}}_4^{2-} $侵蚀为主，相同离子浓度侵蚀损伤程度为：${rm{ SO}}_4^{2-}$>${rm{ SO}}_4^{2-} $ & ${rm{Cl}}^- $混合液>${rm{Cl}}^- $>清水。研究结果可为海水倒灌、地下水污染等具有离子侵蚀环境条件下的注浆结石体劣化防治提供参考依据。

An analysis of the deterioration mechanism of a grouting stone under the ion erosion

Research on the degradation mechanism of cement-water glass grouting stones (C-S stones) in an environment of ion erosion is lacking. The unconfined compressive strength test is conducted to analyze the change law of macro-mechanical properties of the C-S calculus body under different age conditions after the erosion of three different concentrations of sulfate. A combination of SEM, EDS and XRD is used to observe the mesostructure and chemical composition changes of the stone body, and reveal the mechanism of ion erosion damage of the grouting stone body. The results show that within 28 days of erosion, different concentrations of ionic solutions has no significant effect on the growth of stone strength. From 28 to 90 days of erosion, the growth of stone strength in high concentration solution is significantly degraded, and when the concentration of ${rm{ SO}}_4^{2-} $ solution is 20 g/L, the 90 d intensity value of the stone body is only 2.43% of the 28 d intensity value. The chemical composition of the stone body changes under the influence of ion erosion, which destroys the stability of the internal structure and greatly reduces the compressive strength. For the C-S stone body, the main damage of ion erosion is ${rm{ SO}}_4^{2-} $ erosion, and the degree of erosion damage is ${rm{ SO}}_4^{2-} $ > ${rm{ SO}}_4^{2-} $ & ${rm{Cl}}^- $ mixed solution > ${rm{Cl}}^- $ > clear water under the same ion concentration solution. The research results may provide a reference for the prevention and control of the grouting stone body deterioration under the ion-eroded environmental conditions such as seawater inversion and groundwater pollution.