The Effect of Deformation Parameters of Clay-Core on Arching Behaviour of Rockfill Dam

Abstract

In zoned embankment dams, horizontal and vertical cracks developing in the upstream-downstream direction for various reasons cause internal erosion, resulting in serious consequences such as dam failure. Hydraulic fracturing is one of the mechanisms that cause these cracks to develop in the upstream-downstream direction. Hydraulic fracturing occurs when the stresses at the upstream face of the core are less than or equal to the hydrostatic stresses originating from the reservoir. The arching phenomenon creates the stress environment in which hydraulic fracturing can develop. In transverse arching, one of the arching types, stress transfer occurs from the core to the transition and shell zones. As a result of this stress transfer, the vertical stresses on the upstream surface of the clay core decrease. This study examines the effect on zoned dam transverse arching behavior in combinations where the geomechanical characteristics of the clay core (Elasticity modulus and Poisson ratio) change, provided that the material characteristics in the transition and shell zones are constant. Numerical analyses were carried out using the finite element method using the maximum cross-section of Çınarcık Dam. As a result of numerical analysis, it was seen that the increase in the elasticity modulus and Poisson ratio values, which are the deformation parameters of the clay core, was effective in reducing the transverse arching potential.