|
Abstract Both the pressure plate and vapor transfer technique are used to measure the soil-water characteristic curves(SWCCs) of bentonite-sand mixtures for understanding the effects of initial saturated condition，sand mix ratio and dry density on water-holding capacity in drying process. With respect to the bentonite-sand mixtures saturated under confined condition，it is found that the water-holding capacity decreases with the increase in sand mix ratio and dry density. While for the bentonite-sand mixtures saturated under free condition，the water-holding capacity is found to be constant with different dry densities. By introducing the effective clay density and the effective water content，the measured SWCCs of bentonite-sand mixtures are modified to illustrate the major factors controlling the water-holding capacity of mixtures under different saturated conditions. It is found that the water-holding capacity of mixtures saturated under confined condition is mainly controlled by effective clay density；while that saturated under free condition is mainly controlled by sand mix ratio. The empirical equations of modified SWCCs of GMZ001 bentonite-sand mixtures with various sand mix ratios are fitted based on test data，and they can be used to estimate the unsaturated water content of the mixed backfill/buffer material in high-level waste disposal project.
|
|
Received: 10 September 2010
|
|
|
|
2011, Vol. 30 
