含盐量对蒙脱石粘土电渗影响试验研究

为了研究电场作用下含盐量不同的蒙脱石粘土的渗透特性，利用自制的室内电渗试验装置，完成了4种含盐量的蒙脱土电渗试验，对试验过程的排水量、电流、电势及试验后含水率进行监测。结果表明:蒙脱土在电场作用下的渗透性显著增大，40V电压情况下电渗排水速率约为常规渗透速率的1000倍；受蒙脱石自身分子结构及电解质浓度的影响，电渗系数随含盐量的增加先增大后减小，在0.5%附近达到最大排水量；土体两端有效电势随含盐量增加而减小，电流反之增大，阴阳两极电势降增大，表明界面处的能耗随含盐量增加而增大；阴阳两极板短接后，电渗过程中电荷发生重分布，电渗结束后，土体内电势分布不均匀，中间区域电势最低，土体各处电流方向不一致。 

Experimental Study on Effect of Soil Salinity on Electro-Osmosis in Montmorillonite Clay

In order to investigate the permeability of montmorillonite clay with different salt content under an electric field, a laboratory device was designed to capture the drainage, current intensity, voltage, and water content during electro-osmotic drainage tests at four different salinities in montmorillonite. The results show that the permeability increased significantly during electro-osmotic drainage in the electric field. Under 40 V voltage the drainage rate in electro-osmosis was as large as 1 000 times that in normal drainage tests. The electric permeability coefficient increased first and then decreased with an increase in the salt content because of the effect of montmorillonite molecular structure and electrolyte concentration. When the salt content was near 0.5%, the drainage reached a maximum. With the salt content increasing, the effective potential of the soil decreased but the current and the potential drop between cathode and anode increased, reflecting that the energy consumption at the interface increased with the increase of salinity. In addition, a short-circuit connection between the cathode and anode electrodes resulted in a charge redistribution in the process of electro-osmosis. After the electro-osmosis, the potential distribution was found not uniform: the potential of the middle region was the lowest, and the direction of current was different in the soil.