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Evaluating the seismic stability of a rock slope typically involves searching for the minimum value of calculated safety factors (SF) for each supposed sliding block. Because only the transient equilibrium is evaluated, the likelihood of any slope failure can be deemed negligible if all the calculated SFs are greater than unity. However, even if some of the calculated SF are less than unity, it cannot be assumed that the slope will collapse. Recently, in the wake of extremely large earthquakes in Japan, the design earthquake standards for nuclear power plants (NPP) have been extended. After the experience of the 2011 off the Pacific coast of Tohoku Earthquake, the designer is expected to consider beyond design basis earthquakes to determine whether more can reasonably be done to reduce the potential for damage, especially where major consequences may ensue [IAEA (2011). IAEA international fact finding expert mission of the Fukushima dai-ichi NPP accident following the Great East Japan Earthquake and Tsunami, Mission report, IAEA]. With this in mind, the method employed to evaluate the seismic performance of the slope surrounding an NPP needs to be capable of doing more than determining the likelihood of failure: it must also consider the process toward failure in the event of an earthquake beyond the design basis. In this paper, a new evaluation flow which considers the failure process is proposed to evaluate the seismic performance of slopes surrounding an NPP. This is followed by confirming the validity of the concepts in the proposed flow chart by re-evaluating centrifuge tests in past literature and the numerical simulations designed for those tests. [ABSTRACT FROM AUTHOR]

This study investigated the applicability of a nonlinear analysis method that considers progressive failure to evaluating the stability of rock slopes, including post-earthquake residual displacement. The vibration step of the nonlinear analysis, which begins after residual displacement occurs, was found to match that of a dynamic centrifugal model test. The nonlinear analysis was concluded to be relatively conservative because it calculated a slightly larger residual displacement than that observed during the model test. A real-scale soft rock slope was analyzed, and the results showed that the proposed analysis method is useful for evaluating slope seismic stability, including post-earthquake residual displacements. [ABSTRACT FROM AUTHOR]