Abstract:

The soil-water characteristic curve is divided into four segments based on the main factors affecting the hydraulic conductivity coefficient of unsaturated soil. On this basis, a segmentation simplified model for hydraulic conductivity of unsaturated cohesionless soil with bad gradation was created. A complete predictive curve can be obtained just with a small amount of measured or calculated hydraulic conductivities of different moisture conditions. Curve of lnK-lnΨ at low matric suction(0<ψ<ψ_a)and curve of lnK-lnθ when θ_b<θ<θ_a are verified to be linear.

Key words: unsaturated soil, hydraulic conductivity, segmented simplified model, soil-water characteristic curve, matric suction