Shaking table test to assess seismic response differences between steep bedding and toppling rock slopes

Abstract

In order to investigate the seismic response of steep bedding and toppling rock slopes, a large-scale shaking table test was performed taking into consideration a variety of factors such as slope type and input seismic excitation. Diverse seismic responses, including acceleration and earth pressure at several locations, were analyzed in terms of the test results. It was found that the slope type has a significant impact on the failure mechanism and response norm of different kinds of rock slopes. Firstly, the slide surface of the steep bedding rock slope is basically parallel to the slope surface, while that of toppling rock slope skews the rock layer under seismic load. The failure zone area of the toppling rock slope is smaller than that of the bedding rock slope, which is mainly because it consumes plenty of seismic energy to break through the rock layer of the toppling rock slope. In addition, for acceleration along the vertical direction, an abrupt amplifying effect exists at the top slope when the peak input motion acceleration (PIMA) exceeds a certain value: 0.6 g for a bedding rock slope and 0.4 g for a toppling rock slope. Meanwhile, for acceleration along the horizontal direction, the acceleration amplifying factors of toppling rock slopes are larger at the slope surface but smaller at the inner slope portion than that of bedding rock slopes. Furthermore, the acceleration amplifying factor is larger than the earth pressure amplifying factor at the slope surface. The earth pressure amplifying factor at the top surface for a toppling rock slope is close to that of a bedding rock slope with an increase in PIMA. This novel experiment reveals the different failure mechanisms between steep bedding and toppling rock slopes, as well as being of help to the conduct of further study on seismic hazard early warnings.