MODIFIED NEWMARK APPROACH FOR EVALUATION OF EARTHQUAKE–INDUCED DISPLACEMENT OF EARTH DAM- APPLYING FOR RE-DIVISION OF SLIDING MASS

The conventional Newmark sliding block approach for evaluating the earthquake-induced displacement of earth dams is widely used in practice. However, the change in the position of the sliding mass with time when a slip occurs is not taken into account in the conventional Newmark approach when calculating the seismic displacement during an earthquake. Thus, a modified Newmark analysis is presented here in order to consider the influence of the changing position of the sliding mass on the estimated seismic displacement of an earth dam by re-dividing the sliding mass. A comparison of the results of the conventional and the modified Newmark approaches shows that ignoring the change in the sliding mass position over time can lead to the overestimation of the sliding displacement, especially if the Fellenius method, a less rigorous method, is used for evaluating the yield seismic intensity. In this study, the modified Newmark approach, using a relatively easy method among strict methods (simplified Bishop method), leads to a more realistic assessment of the permanent displacement in seismic slope stability analyses.