Evaluating the Saturated Permeability Coefficients of River Embankments via Field Permeability Tests

The authors conducted field permeability tests on numerous river embankments using a Marriott siphon in 30-cm test holes to obtain their saturated permeability coefficients. The results revealed that the field-obtained saturated permeability coefficients were larger than those obtained as a result of the laboratory permeability test conducted on the undisturbed specimens sampled from the same location. Regarding embankments constituted by fine-grained soils, there are cases in which the field-obtained coefficients are several orders of magnitude larger than those obtained under laboratory conditions. These results suggest that the field permeability coefficient obtained by the Marriott siphon with large-diameter test holes evaluates the macroscopic permeability, including in situ heterogeneity and anisotropy. In this study, the results of the field permeability tests at two embankments of the Oda and Kano Rivers are shown. In addition, the results of the laboratory permeability test for the undisturbed specimens sampled at each field site are shown. In each survey, the field permeability coefficients were larger than both the laboratory permeability coefficients and the estimated value from particle size, as in the case of other embankments investigated so far.