Moisture migration test investigation about subgrade filled with different soil

In order to study how soil influence water migration, which infiltrate subgrade, and the law of water migration, we use low liquid limit clay, silt and fine sand as research object. Real time water content in these samples without being destroyed were monitored. The dynamic observation is implemented by the moisture sensor and the data acquisition facility (6050X1 trase system).According to data, we can draw time-variety curve of the volume fraction of soil water content, curve of migration rate of wetting front and curve of infiltration rate. The results show that different water permeability and capacity of different soil influence seepage. Fine sand has the best permeability, low liquid limit clay is the worst, silt is between them. Each test-piece´s upper soil´s water content has significant changes. Along with moisture infiltration, water content increase at first, then decrease, at last to stable.