Explanation of Phenomenological Characteristics in Seepage Force Concept System

Soil mechanics has been developed for a long time and its concept system is basically complete. But there are still some concepts not being defined clearly. The unclear concepts of seepage force are stated from three phenomenological characteristics aspects in this paper. The difference between loaded object and calculated range is cleared. The contact rule of solid phase and liquid phase is illustrated. The mathematical meaning of seepage force is clarified. Though judging the critical hydraulic gradient of soil flow on surface of cohesionless soil, the difference and correlation of the soil particle and clod analysis based on the phenomenological characteristics will be illustrated.