Analysis of behaviour of a high rockfill dam

Abstract

This paper reviews the effects of first impounding on rockfill dams. In particular, saturation collapse phenomena induced by wetting of rockfills are highlighted. Major attention is given to the effects of impounding-induced saturation on the mechanical behaviour of rockfills. The paper presents a comprehensive study of the behaviour of the Masjed-E-Soleyman rockfill dam during its construction and first impounding, by means of thorough analyses of instrumentation results and numerical modelling. Results of the instruments show that impounding-induced saturation collapse has occurred in the upstream shell of the dam. Also, the numerical analyses suggest that the Hardening Soil, elasto-plastic constitutive model employed in the analysis, using reduced strength and stiffness parameters for the saturated rockfills, is able to capture the behaviour of the rockfill dam during the first impounding. The results of the analysis compare well with the similar results of the instrument monitoring.