Mechanical Characteristics of Expansive Soil Contaminated by Manganese Ions
In response to the mechanical characteristics of contaminated expansive soil,unconfined compressive strength and direct shear tests were conducted to explore the changes in mechanical charac-teristics at the macroscopic level,combining SEM experiments to analyze the changes in microstructure.After XRD experiments,JADE analysis software was used to quantitatively analyze the collected raw da-ta and obtain the trend of changes in the proportion of each phase content in the sample,in order to ex-plore the mecha-nism of changes in the mechanical properties of expansive soil.The experimental results show that under the same compaction degree and Mn2+concentration,the expansive soil sample with the optimal moisture content has the highest strength;Under the same initial moisture content,the strength,internal friction angle,and cohesion of the sample all show an increasing trend with the increase of Mn2+concentration;Quantitative analysis of the phase by JADE indicates that SiO2 in the soil shows an increasing trend after being contaminated with Mn2+.The reason is that the hydrolysis of Mn2+in MnSO4 solution indi-rectly leads to the hydrolysis of silicate minerals in the expansive soil sample,releasing SiO2 and increasing the bonding effect between soil particles,thereby improving the overall integrity and stability of the soil.
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