An investigation into the seismic behaviour of dams using dynamic centrifuge modelling

Abstract

Dynamic response of dams is significantly influenced by foundation stiffness and dam-foundation interaction. This in turn, significantly effects the generation of hydrodynamic pressures on upstream face of a concrete dam due to inertia of reservoir water. This paper aims at investigating the dynamic response of dams on soil foundation using dynamic centrifuge modelling technique. From a series of centrifuge tests performed on model dams with varying stiffness and foundation conditions, significant co-relation was observed between the dynamic response of dams and the hydrodynamic pressures developed on their upstream faces. The vertical bearing pressures exerted by the concrete dam during shaking were measured using miniature earth pressure cells. These reveal the dynamic changes of earth pressures and changes in rocking behaviour of the concrete dam as the earthquake loading progresses. Pore water pressures were measured below the dam and in the free-field below the reservoir. Analysis of this data provides insights into the cyclic shear stresses and strains generated below concrete dams during earthquakes. In addition, the sliding and rocking movement of the dam and its settlement into the soil below are discussed.

Experimental Investigation of Seismic-Induced Hydrodynamic Pressures on a Vertical Wall under Conditions of Wave Resonance

“…Chen and Malenica [13] examined the distributions of hydrodynamic pressure on the surface of a ship hull for a large range of encounter frequencies. Saleh and Madabhushi [14,15] investigated the effect of dam-foundation interaction on the hydrodynamic pressure response on a dam face under different seismic excitations using the dynamic centrifuge modeling technique. This work proposed an experimental method for examining hydrodynamic pressure.…”

Imaging the failure of a rock-fill dam following liquefaction

“…The hydro-dynamic effects on any dam structure owing to the reservoir water can be quite significant during earthquake loading. Recent research by Saleh and Madabhushi (2010a, 2010b, 2010c established the magnitude of the hydrodynamic forces on concrete dams under earthquake loading and compared the results to the theoretical predictions made using analytical solutions suggested by Chopra (1967) and Chopra and Chakrabarti (1981). Although some results may be applicable to all types of embankments, the use of rock-fill will permit relatively faster drainage at the dam-foundation interface compared to earth-fill.…”

“…This is true for the cases where finite-element modelling of earth dams was used (Seed et al, 1975b) or using dynamic centrifuge modelling (Adalier et al 1998;Saleh and Madabhushi, 2010a, 2010b, 2010c. Rock-fill dams, on the other hand, will locally apply stress to the volume of sand directly under each rock leaving small unstressed wedges between the rocks.…”