Infiltration measurements in model embankments composed of volcanic sandy soils

To study seepage behavior caused by rainfall, field tests were carried out on model embankments that consisted respectively of Hachinohe Shirasu and Tsukidate soil. They are volcanic pyroclastic sediments with pumice that exist in Aomori and Miyagi Prefectures in Japan. Due to rainfall the maximum value of water content in earthfills which consist of Hachinohe Shirasu and Tsukidate soil were 40-42 percent and about 42 percent respectively. Their peak had tend to occur after each 1day and 2.5day of rainfall peak. Furthermore from the field test results, storage coefficient, which is normalized by porosity, at wetting process was 0.01-0.25 in Hachinohe Shirasu and Tsukidate soil. Subsequently, using hydraulic properties determined from laboratory tests, finite element analyses of saturated-unsaturated seepage in those embankments were performed. Comparing the calculated behavior with measured one for about three months data, after 20 days we could conclude that the calculated seepage behavior agreed with observed one. Copyright ASCE 2006.