EFFECT AND CHARACTERIZATION OF SALT SOLUTION ON HYDRAULIC CONDUCTIVITY OF QUARTZ POWDER-BENTONITE MIXTURE

This paper used the variable head permeability test and measured the hydraulic conductivity values of the mixtures of quartz powder and bentonite in distilled water and NaCl and CaCl₂ solution with different concentrations. It further used the magnetic resonance test(MRI) and the environmental scanning electron microscope(ESEM) and analyzed the pore distribution characteristics of the mixture saturated with different pore fluid salinity. It investigated the effect of pore fluid salinity and bentonite content on the hydraulic conductivity of the mixtures. The results show that the hydraulic conductivity of the mixture of quartz powder increases obviously under the action of salt solution, and the pore distribution also has obvious difference. At last, using the concept of clay porosity ratio(e_b) was adopted and established a new characterization formula of hydraulic conductivity of quartz powder bentonite mixture under the action of salt solution. Compared with the existing formula, the new formula can better predict the hydraulic conductivity of quartz powder-bentonite mixture under the action of salt solution.