Temporal variation in the permeability anisotropy behavior of the Malan loess in northern Shaanxi Province, China: an experimental study

摘要

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 (K-h) and saturated vertical hydraulic conductivity (K-v) of loess samples were measured using variable head permeability tests. The K-h and K-v values indicate that the loess exhibited permeability anisotropy in space and time, and K-h and K-v at different depths decreased as seepage time increased. K-h-time showed an exponentially decreasing trend, and K-v-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 K-h and K-v values of the loess tended to decrease with depth, as described by an exponential decay model.