不同pH条件下红层泥岩崩解特性研究

Disintegration characteristics of red bed mudstone under different pH conditions

研究红层泥岩在不同酸碱环境中的崩解特性对保障红层泥岩人工边坡、地基工程的安全性十分重要。通过开展pH为3,7,11条件下红层泥岩的崩解试验,深入了解了红层泥岩在不同酸碱环境下的崩解现象,分析了干湿循环后红层泥岩粒径级配特征、不均匀系数、曲率系数、比表面积增量及崩解率及崩解比的变化规律,揭示了红层泥岩在不同pH条件下的崩解机制。研究表明:pH=3时,红层泥岩崩解现象最剧烈,裂缝出现最早,贯通速率最快;干湿循环后粒径级配均表现出大颗粒减小,小颗粒增多;与pH=7相比,pH=3和11的环境对红层泥岩崩解后颗粒的不均匀系数及曲率系数影响更加明显,增长幅度更大;红层泥岩崩解率与崩解比的变化速率在不同酸碱环境中从大到小依次为pH=3>pH=11>pH=7;在酸性条件下,红层泥岩的比表面积增幅最快,远高于碱性和中性环境。研究成果可为红层泥岩边坡及地基的稳定性分析及工程实践提供参考。

The disintegration characteristics of red mudstone under different pH conditions are very important for the safety of slopes and foundation engineering.The disintegration phenomenon of red bed mudstone under different pH conditions was investigated by conducting disintegration tests of red mudstone at pH 3,7 and 11.Moreover,the variation patterns of grain size gradation,inhomogeneity coefficient,curvature coefficient,specific surface area increment,disintegration rate and disintegration ratio of red-bedded mudstone specimens after dry and wet cycles were analyzed in detail,revealing the disintegration mechanism of red-layered mudstone under different pH conditions.The red mudstone showed the strongest degradation phenomenon under pH 3 with the earliest initial crack and the fastest penetrating rate.The particle size gradation after dry and wet cycles both showed a decrease in large particles and an increase in small particles.The influence of environment of pH=3 and 11 on the inhomogeneity and curvature coefficients of particles after disintegration of red-bedded mudstone were more obvious compared with pH=7.The change rate of the red-bedded mudstone disintegration rate and disintegration ratio from large to small is pH=3>pH=11>pH=7.Under acidic conditions,the specific surface area of red-bedded mudstone increased fastest,much higher than that in alkaline and neutral environments.The research results can provide reference for stability analysis and engineering practice of red bed mudstone slopes and foundations.