氯盐和硫酸盐对遗址土体颗粒级配和界限含水率影响的对比

Comparative study of the influence of chlorine and sulfate salt on grain size distribution and limit moisture content in site soils

为了探讨盐分对遗址土体颗粒级配和界限含水率的影响,通过室内试验,对洗盐后的素土分别以0(素土),0.2%,0.4%,0.6%,0.8%,1.0%的梯度加入NaCl,Na_2SO_4两种可溶盐,测试特定盐分质量分数和类别的含盐土的颗粒粒径分布和界限含水率的变化.试验结果表明:盐分对遗址土体的颗粒级配有一定的影响,尤其对黏粒占比的变化影响显著,随着盐分质量分数的增大,分布在细粉粒和黏粒范围内的颗粒占比相对减小,分布在粗粉粒和砂粒范围内的颗粒占比相对增加,并且Na_2SO_4盐对土体颗粒级配的影响比NaCl盐的显著;随着盐分质量分数的增大,含盐试样的液限含水率、塑限含水率以及塑性指数均逐渐减小,试样由粉质黏土变为粉土,由于盐分的加入,盐分作为电解质对土粒产生团聚作用,黏粒被吸附,使得试样中黏粒占比相对减少.

In order to explore the influence of salt content on particle size distribution and limit moisture content on site soils,a test was carried out joining two soluble salts with the gradient of 0（desalination soil）,0.2%,0.4%,0.6%,0.8%,1.0%of NaCl and Na_2SO_4 to the desalination soil,to discover the distribution of particle size and the changes in moisture content.The results showed that salts had certain effects on particle size distribution,especially a significant effect on the change of clay content and the content of distribution within the scope of fine silt;clay particles decreased relatively and the distribution within the scope of coarse silt particles and sand content relatively increased with the increase of salt content;the salt of Na_2SO_4 had a more significant influence on grain size distribution than NaCl.The liquid limit moisture content,plastic limit moisture content and plasticity index of salt samples decreased gradually with the increase of salt content,and the samples of silty clay changed into silt.The addition of salt as an electrolyte had reunited effects on soil particles and clay adsorption and resulted in the relatively less content of clay in the soil samples.