Seismic response evaluation of a CRFD considering its precise 3D geometry and the surrounding valley

The response of the concrete face slab is considered as the key issue for the sustainability of a Concrete-Face Rockfill Dam (CFRD). Further to the response under static loads, earthquake excitation may induce strains to the face slab developing extreme stress concentration. Appropriate design is therefore necessary to ensure face sustainability, prevent damage of the individual concrete panels and safeguard impermeability. Dynamic numerical analyses for investigating the response of CFRD under seismic action have been performed at early 90’s, limited however to plain strain analysis. As a result, only deformation normal to the face slab, strains, and stress along the length of the concrete panels could be derived. Recent development of computational resources and advances in numerical expertise allowed for 3D refined mesh implementation with appropriate simulation of most relevant mechanisms governing the interaction between the slabs and the rockfill, including slab contact activation-de-activation at vertical joints. In the initial attempts the valley was disregarded and afterwards was incorporated with a simplified V shape. With the purpose of the response evaluation of Messochora dam and the effect to the slab face under seismic action, a refined mesh of the computational domain was derived, including the geometrical variations at the left and right side of the dam-canyon interface. The response of the dam under the characteristic input motions was assessed and the behaviour of the concrete face was also evaluated by establishing the range of deformations, strains, stresses ad movements of the individual concrete panels.