Seismic Dynamic Response of Rock Slope Under Near-Fault Multi-Pulse Ground Motions

Previous studies on near-fault pulse-like ground motions have mainly focused on single-pulse motions,with limited research on multi-pulse motions.To extract multi-pulse ground motions,a method combining generalized continuous wavelet transform (GCWT) and parameter evaluation is employed.Seven non-pulse,single-pulse,and multi-pulse ground motions from the Chi-Chi earthquake in Taiwan were identified from the PEER NGAWest2 database.A comparison of response spectra reveals that multi-pulse ground motions exhibit significantly larger spectral velocities than non-pulse motions,with multiple peaks in the long-period range.Using a discrete element program,the dynamic response of bedding rock slopes under different types of ground motions is analyzed.The results show that:(1)Multi-pulse ground motions generate a deeper potential slip zone and a larger landslide volume.(2)Seismic amplification increases nonlinearly with elevation under non-pulse and single-pulse motions,with stronger amplification at the slope crest for single-pulse motions. In contrast,multi-pulse motions show stronger amplification below mid-slope,with similar amplification above mid-slope as non-pulse motions.(3)The maximum horizontal displacement under multi-pulse motions is approximately three times larger than that under non-pulse and single-pulse motions,indicating a significantly higher risk to slope stability.These findings underscore the critical impact of multi-pulse ground motions on slope stability and structural damage.