| Japanese guidelines for evaluating the seismic performance of dams against large earthquakes (draft) define the seismic performance required against extremely large earthquake motions. The most important requirement is that the storage function of a dam is maintained, which means that an uncontrolled release of stored water does not occur. A dynamic analysis considering the critical damage process by the generation of tensile cracks is conducted to evaluate the seismic performance of a concrete gravity dam under the guidelines. If the estimated cracks do not penetrate completely between the upstream and downstream faces of the dam body, the storage function is judged to be maintained. However, no method has been established to evaluate the seismic performance of a concrete dam taking into consideration the stability of the upper block after the dam body is divided due to penetrated tensile cracks.This paper discusses a method for evaluating the ultimate stability of concrete gravity dams in this situation, based on findings from shaking table tests and numerical analyses. A fundamental study on the effect of uplift pressure that might be generated along the detached interface is also introduced. |
