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为研究铅污染物对黏土微观结构演化和变形特性规律的影响,通过SEM表面微观形貌试验、低温氮吸附试验,研究铅污染黏土的表面微观形貌与孔隙结构特征,微观结构试验结果表明:未受铅污染的原状土颗粒孔隙较少,颗粒以叠片状排列为主;铅污染黏土孔隙发育明显,主要以10 nm左右的中孔为主;随污染物浓度增大,污染黏土的孔径增大,二次孔增多,土颗粒以点–点排列为主;通过开展无侧限抗压强度试验、直剪试验和固结试验,观察铅污染黏土的强度与变形特性,铅污染物对黏土无侧限抗压强度影响显著,随铅污染物浓度的增大,铅污染黏土无侧限抗压强度明显减小。随铅污染物浓度增大,污染黏土抗剪强度减弱,黏聚力c和内摩察角减小。在铅污染物化学溶液的腐蚀作用下,黏土孔隙比e变大,随铅污染物浓度增大,压缩系数和压缩指数cC增大,压缩模量sE减小。
In order to study the influence of lead pollutants on the evolution and deformation characteristics of clay microstructure, the surface morphology and pore structure of lead contaminated clay were studied by SEM surface morphology and nitrogen adsorption at low temperature. The microstructure test results showed that: Lead-contaminated intact undisturbed particles had fewer pores and arranged mainly in lamellar order. The lead-contaminated clay had obvious pore development, mainly dominated by 10 nm mesopores. With the increase of pollutant concentration, the pore size of contaminated clay And the secondary pores increase. The soil particles are mainly point-point arrangement. Through the unconfined compressive strength test, direct shear test and consolidation test, the strength and deformation characteristics of lead-contaminated clay are observed. Unconfined compressive strength of clay has a significant impact. With the increase of lead concentration, the unconfined compressive strength of lead contaminated clay decreases obviously. As the concentration of lead contaminants increases, the shear strength of the contaminated clay diminishes, and the cohesion c and the Nepomu angle decrease. Under the corrosive action of chemical solution of lead contaminants, clay porosity ratio e becomes larger. With the increase of lead concentration, the compressibility and compressive index cC increase, and the compressive modulus sE decreases.