Three‐Dimensional Analysis of Pressures on Dams

Abstract

A span‐wise variation of nonlinear hydrodynamic pressures on dams during earthquakes was studied using a finite‐difference approximation of Euler's equations coupled with the nonlinear free‐surface boundary condition. The pressure distribution was sensitive to both the longitudinal and lateral components of the ground motion. The dynamic effect of reservoir banks would increase with the dam width. The inward motion of a reservoir bank produced higher pressures on one side while the outward motion of the other bank resulted in a reduction in hydrodynamic pressures. The combined effect can be effectively obtained when the geometric parameters of a dam/reservoir system, the changes in water surface, and the earthquake force are cast in the equations of motion. In this case, the time‐dependent water surface is transformed to the horizontal plane, and the flow field is mapped onto a cubic region, making it convenient to model the complex reservoir geometry and the wavy water surface by the finite‐difference method.