A generalized dilatancy angle equation of granular soil

This paper presents a generalized dilatancy angle equation of granular soil to cover not only the drained tests but also the undrained tests by introducing a generalized structure of soil: soil skeleton formed by soil particles and the fluid in soil voids, under the assumptions of the incompressibility of soil particles and the compressibility of the fluid in soil voids. For the drained tests, the generalized dilatancy angle equation of granular soil would be degenerated to its current dilatancy angle equation. However, for the undrained tests, the generalized dilatancy angle equation of granular soil was derived with a \lambda parameter that was related to the stress-strain state of soil and the nature of the fluid in soil voids. The \lambda parameter was determined by the initial dilatancy angles of granular soil at the onset of shearing on the same initial state of the soil in the drained and undrained tests. In addition, the generalized dilatancy angle equation of granular soil was verified for application in calculation of the dilatancy angles of sands in the drained and undrained tests.