LAUSR

By analyzing a fresh soil section and soil samples from Yan’an New Area, northwest China, an engineering shallow loess slope was investigated. Temporal variation in the saturated horizontal hydraulic conductivity (Kh) and saturated vertical hydraulic conductivity (Kv) of loess samples were measured using variable head permeability tests. The Kh and Kv values indicate that the loess exhibited permeability anisotropy in space and time, and Kh and Kv at different depths decreased as seepage time increased. Kh-time showed an exponentially decreasing trend, and Kv-time showed a linearly decreasing trend. Analysis of the initial state and micromorphological features of the loess indicate that the orientation of soil particles in the deposition process may be inherently anisotropic. The Kh and Kv values of the loess tended to decrease with depth, as described by an exponential decay model.