This example concerns the stability of a reservoir dam under conditions of drawdown. Fast reduction of the reservoir level may lead to instability of the dam due to high pore water pressures that remain inside the dam. To analyse such a situation using the finite element method, a transient groundwater flow calculation is required. Pore pressures resulting from the groundwater flow analysis are transferred to the deformation analysis program and used in a stability analysis. This example demonstrates how deformation analysis, transient groundwater flow and stability analysis can interactively be performed in PLAXIS 2D.

The dam to be considered is 30 m high and the width is 172.5 m at the base and 5 m at the top. The dam consists of a clay core with a well-graded fill at both sides.