Simulation of collapse settlement of first filling in a high rockfill dam

• We developed a model to predict collapse settlement in rockfill due to saturation.
• Some large scale triaxal tests are used to prepare collapse parameters in rockfill.
• This model is used to predict the collapse settlement in a high rockfill dam.
• The modeling results are in good agreement with those from field instrumentation.
• The more stages in raising water level, the less displacements in the upstream shell.

In this paper, a new collapse prediction framework is proposed, involving an introduction of a stress dependent collapse coefficient which is directly obtained from results of triaxial tests. Within the proposed framework, the collapse settlement of rockfill dams can be simulated for first impoundment analysis. To make an appropriate choice of the model parameters, some large-scale triaxial collapse tests are numerically modeled employing the proposed framework and the parameters are used for simulation of collapse settlement of Gotvand, 178 m high rockfill dam, and verified by field measurements and monitoring data. The influence of first filling rate on the deformation field of the dam body is discovered using a different number of stages for the impoundment. A parametric study has been undertaken with regard to the newly introduced collapse coefficient which contributes to the better understanding of collapse phenomenon.