u-w  Finite Differences Method to Analyse Two Compression Waves-of Saturated Soil
Yang Jun,Song Erxiang,Chen Zhaoyuan 
(Department of Civil Engineering, Tsinghua University, Beijing 100084, China)

Abstract: In this paper, the u-w  finite difference formulations of saturated soil are proposed and the stability criterion is given. By this method, two different 1-D initial and boundary problems are solved: one is soil column subjected at the surface to step water pressure boundary condition, the other is soil column subjected at the surface to step displacement boundary condition. The boundary conditions of displacement are input by differention. Compared with the analytical solution, the finite difference results are proved to be quite right a t the trend of change and some key values. The influence of permeability coefficient and volume modulus ratio of fluid and soil skeleton to the two compression waves is also discussed.
Keywords: saturated soil, finite differences, two types of compression waves, soil-porous fluid interaction.