NEW TECHNIQUES FOR MODELING RESERVOIR-DAM AND FOUNDATION-DAM INTERACTION

A hybrid numerical procedure is proposed for the dynamic frequency dom ain response of earth dams resting on a multi-layered foundation. The impounded fluid is assumed viscous to account for the internal viscosi ty and absorption at the reservoir bottom. A new technique is describe d to determine the frequency-dependent added masses and loads contribu ted by the reservoir at the inclined upstream dam face. The impedance of the multi-layered foundation is obtained using the layer transfer m atrix and the dam is modelled by finite elements. An interface functio n is defined using interpolating functions to maintain equilibrium of interface forces and the displacement compatibility at the interface n odes. Unlike other boundary elements, this procedure avoids any additi onal discretization of the fluid and the foundation except at their in terfaces with the dam structure. Numerical results, including transien t reponses to the S90W El-Centro earthquake groundmotion (1940), are p resented to illustrate the modelling of reservoir-dam and soil-dam int eraction. (C) 1997 Elsevier Science Ltd.