A generalized plasticity model to predict behaviors of the concrete-faced rock-fill dam under complex loading conditions

Abstract

This research developed an elastoplastic model within the framework of the generalized plasticity theory, to predict behaviors of coarse-grained soils under complex loading conditions. The stress dilatancy relationship was validated using test results of several kinds of coarse-grained soils; loading direction was proposed considering the strength properties of the coarse-grained soils (i.e. stress ratio at the failure decreases with the increase of the mean stress); and modifications were also made to the plastic modulus of the basic model, so that greatly reduces the difficulty in determining the model parameters. In order to simulate the soil behaviors under cyclic loading conditions, reloading and unloading plastic moduli were also respectively defined. The proposed model was then evaluated using test results of the Granite rock-fill in different stress paths (including both monotonic loading and cyclic loadings). Finally, the proposed model was used to analyze the deformation of the Shuibuya Concrete-Faced Rock-fill Dam. Model parameters of the main rock-fill and secondary rock-fill were back analyzed from large-scale plate-loading tests. The numerical results were also compared with the in situ measurements. Results showed that the proposed model can give reasonable predictions of the dam behaviors during the construction and full storage period; and permanent deformation that was caused by fluctuations of water level can also be predicted.

Keywords:

• elastoplastic model
• coarse-grained soils
• dilatancy equation
• nonassociated flow rule
• plastic modulus
• Shuibuya CFRD