The filter paper method and the pressure plate method are used for measuring the suction of Gaomiaozi bentonite-sand mixtures. The soil-water characteristic curves (SWCC) obtained during drying from the tests at different void ratios and different mixing ratios of Gaomiaozi bentonite to Fujian sand are compared. The effects of void ratio and the mixing ratio on SWCC are analyzed according to the test results. The results show that when the SWCC is expressed by the relation between suction and saturation degree

the SWCC moves up and right with the decreasing void ratio for a mixture with the same mixing ratio. That’s to say

the saturation degree increases with the decreasing void ratio at a constant suction. Especially when the suction is less than 10 MPa

this phenomenon is evident; at constant void ratios

the SWCC moves up and right while increasing the mixing ratio. In other words

the value of air-entry suction increases with the increasing mixing ratio. In addition

when the mixing ratio and void ratio are the same

the SWCCs of Gaomiaozi bentonite-sand mixture and Kunigel bentonite-sand mixture are quite similar.