Abstract: The non-thickness contact friction element is presented to simulate the mechanical behavior of contact surface between rockfill and concrete retaining wall for Guanyinyan Hydropower Station mixed dam, which makes up of a rockfill dam and a roller compacted concrete gravity dam. The Ducan hyperbola E-B constitutive model is applied to simulate rockfill body and clay core wall’s stress-strain relations. Considering actual construction process and impounding process, sensitivity analysis are performed for varying of configuration shape of concrete connection, which include contact surface slope changing and contact surface rotating to upstream on horizontal plane. Normal stress, contact state and latent water power crack area of contact surface for different configuration shapes of concrete connection can be revealed through sensitivity analysis. So the better configuration shape of concrete connection can be recommended. The three-dimensional nonlinear FEM simulation results show that normal stress on contact surface of clay core wall is all compression stress; the one is smaller when contact surface slope steeper and rotation angle smaller to upstream. In sum the seepage prevention of the fourth design scheme among wrapped connection configuration shape is better than others from a comprehensive consideration, which will be recommended to be the design scheme.

Key words: Guanyinyan Hydropower Station, Mixed dam, Ducan E-B model, contact friction element, three-dimensional nonlinear FEM