Effect of geometry on the natural frequency and seismic response characteristics of slopes subjected to pulse-like ground motions

Abstract

Near-fault regions are particularly vulnerable to seismic-induced landslides due to the intense energy pulses in near-fault ground motions (NFGMs). These pulses, shaped by terrain geometry and material properties, significantly influence seismic response and slope stability. This study investigates the impact of slope geometry on natural frequency and seismic response characteristics under both pulse-like ground motions (PLGMs) and non-pulse ground motions (non-PGMs). The results show that increasing slope height lowers natural frequency, making the slope more susceptible to resonance with seismic waves, thus amplifying ground motion and increasing instability. Similarly, steeper slopes also reduces the natural frequency, heightening instability by up to 0.17%. PLGMs generate seismic responses approximately 7% stronger than those induced by non-PLGMs. Furthermore, as the frequency of PLGMs rises, so does their destructive potential. Material analysis reveals that Rock Class A has a natural frequency 68% higher than Rock Class D, making it significantly resistant to seismic deformation. These insights are essential for designing more resilient slopes in seismic-prone regions.