Abstract:

As the most widely adopted type of dam, earth-rockfill dams are widely recognized for their considerable deformation adaptability and cost-effectiveness. Settlement occurring during and after the construction of earth-rockfill dams can lead to serious hazards. Therefore, accurate prediction and control of dam-body displacement are crucial to construction safety. This paper presents a finite element method (FEM) analysis of the settlement behavior of the Altash dam in Xingjiang. The stress-strain characteristics of the rockfill are examined using both the unified hardening model for clays and sands (CSUH) and the modified Cam-clay (MCC) model. The model parameters are calibrated using a differential evolution algorithm integrated with a modified local search method. The results show that the CSUH model predicts settlement behavior significantly more accurately than the MCC model. This enhanced performance is attributed to the introduction of the parameter p_s, which enables a more comprehensive representation of rockfill compressibility. To further improve the accuracy of settlement prediction, this study proposes an optimization-based calibration method that accounts for the actual settlement behavior of dams and uses only triaxial test data within the strain range observed during construction. The rationality of proposed method is validated through comparison between numerical predictions and monitoring data.

Key words: CSUH model, earth-rockfill dam, dam settlement, stress-strain characteristics, finite element method