Study on Water Vertical Infiltration Characteristics and Water Content Simulation of Sandstone Overlying Loess

Research on the infiltration characteristics of surface water is fundamental for understanding entire hydrological process. Therefore, studying process sandstone slopes overlaid with loess and predicting soil moisture content are great importance investigating processes controlling erosion in hilly gully areas Loess Plateau China. This study mainly focuses simulation vertical movement patterns four kinds (feldspathic argillaceous sandstone) structures covered thin layers loess. In one-dimensional experiment Hydrus-1D model simulation, interlayer transition planes loess–feldspathic loess–feldspathic–argillaceous sandstones were found to present two conditions: fine covering coarse soil. reduced permeability. The existence a layer between feldspathic decreased rate amount decelerated speed wetting front, thereby further affecting ability infiltration. By using model, 15 sets hydraulic parameters, including θx (0.028–0.05795 cm3/cm3), θs (0.2306–0.4786 α (0.01899–0.06071 cm−1), n (1.438–6.408), Ks (1.96·10−4–0.0576 cm/s) inverted optimized each 20 cm (total 60 cm). Van Genuchten constructed these parameters demonstrated high accuracy by coefficient determination R2 > 0.849 relative error RE < 5.311.