Effect of Initial Water Content and Dry Density on Soil Water Characteristics of Compacted Soil
Chang’an University, China

In order to investigate the effect of initial water content and dry density on the soil water characteristics of the compacted soil, the loess used as filling in the Land-making Project of Yan’an new district in China was collected and compacted to two series of samples: one is the same dry density but different initial moisture content, the other is the same initial moisture content but different dry density. The SWCCs of all samples in the range of 0 ~ 105 kPa were measured by the filter paper method. The measured data are fitted with the Fredlund & Xing equation for each dry density. For the samples with different initial water content, the SWCCs show significant differences in the range of 100 ~ 1000 kPa: the retention capacity of water will increase with the initial water content below the range of plastic limit. For the samples with different dry density, The SWCCs show prominent differences in the suction range below 100 kPa while overlapping above this suction. Those suggest that SWCCs of compacted soil with the same dry density are not exactly the same, the effect of initial water content should be considered; and the SWCCs in the high suction range are independent on dry density of compacted soils with the same initial water content, while correlated in the low suction range. This study provide support for further investigation on the unsaturated behaviors of the compacted soil.