Abstract：Tailing dam No.1 of Wushan copper mining is located in Jiangxi province China. The first stage of the tailing dam is the rock-fill dam prected on the soft clay foundation. The treatment of soft clay foundation and the schedule to build rock-fill dam are interpreted briefly. With the development of calculation techniques，the numerical method for consolidation problem has been widely used in engineering practice with satisfying results. Based on soil parameters gained from experiment，back analysis is used to adjust those parameters. By using nonlinear elastic rheology constitutive model and Boltzman inheritance method，the soft clay foundation of tailing dam treated by plastic board is simulated by finite element method (FEM). Comparing numerical results with observation by the displacements of the foundation，those calculated results have a good agreement with those observed results. Based on numerical results，relationships between pore pressure of foundation and time，the displacement of foundation and time，are analyzed. The stress，displacement，and stress state of the rock-fill dam are displayed by some graphs. Some valuable results are derired from those graphs. Condition with creep model and condition without are compared；and the effect on the soft clay foundation is analyzed. The model and those adjusted soil parameters are used to predict the safety state of the rock-fill dam. Numerical simulation proves that the rock-fill dam is safe in the long run and those results gained by numerical method may provide reference to engineering practice.
