黏土固结过程中结合水对粘滞系数影响研究

渗透系数作为土的基本力学指标参数，是孔隙比和粘滞系数的函数，为了研究黏土中结合水对粘滞系数的影响，开展固结试验得到各级压力下的渗透系数与粘滞系数，并由高速离心机分离试验定量测得结合水量。结果表明固结压力增大，孔隙比减小，渗透系数随之减小，由渗透系数计算公式反算出动力粘滞系数，随固结压力增大而线性增大。压力较小时，结合水量变化较小；自由水减少到一定程度变为结合水排出为主。结合水排出会导致结合水膜厚度变薄，粘滞系数随结合水膜厚度减小而线性增大。所以，对于结合水含量较高的黏土，固结压缩过程中存在结合水排出现象，计算渗透系数时需考虑结合水膜变薄导致粘滞系数增大进而对渗透系数产生的影响。

A study on influence of bound water on viscosity coefficient of clays during consolidation

As one of the basic mechanical parameters of soil, permeability coefficient is a function of void ratio and viscosity coefficient. To explore the effect of bound water in the pore of clays on the viscosity coefficient, consolidation test was conducted for permeability coefficient and viscosity coefficient, and centrifuge test was carried out for bound water contents. The result shows that when consolidation pressure increasing, void ratio and permeability coefficient get smaller. Viscosity coefficient calculated based on calculation formulas of permeability coefficient increases lineally with logarithm of consolidation pressures. When pressure is low, bound water content has little change. When free water content decreases to a certain value, the main process is flowing out of bound water. Outflow of bound water leads to a decrease in thickness of bound water layer and viscosity coefficient decreases lineally with the thickness. Therefore, if clays of high bound water content are consolidated and compressed, bound water will flow out and an increase in viscosity coefficient caused by decrease in thickness of bound water layer should be taken into consideration when permeability coefficient needs to be calculated.