Influence of surface wave impedance ratios on the dynamic response and damage characteristics of slopes based on shaking table tests

Abstract

Weathered slopes are often severely damaged during earthquakes, posing challenges to the study of their dynamic response and damage characteristics. In this study, we conducted physical modelling tests using the wave impedance ratio to investigate the influence of weathering layers on slope dynamics through shaking table tests. Model A utilized unweathered rock as a reference, while models B, C, and D included different weathering layers distinguished by varying wave impedance ratios. By comparing the peak acceleration amplification factors (AAFs) of the four models, we found that the AAF increases with increasing wave impedance ratio on the slope surface. Slopes with wave impedance ratio layers exhibited strong dynamic responses above 2/3 of the slope height, with both wave impedance ratio layers and elevation effects playing crucial roles. Further analysis using the Hilbert–Huang transform revealed wider excitation frequency ranges at the top of models B, C, and D than at the top of model A, resulting in resonance effects and significant damage in the top regions of models with higher wave impedance ratios and lower damping ratios. Furthermore, different damage patterns were observed, with the homogeneous model exhibiting a vibration crack–slip mode, while slopes with wave impedance ratio layers experienced cracking, crushing, and debris slipping at the top. This study provides new insights into the dynamic response analysis and stability evaluation of weathered slopes in active tectonic zones.