Analysis of slope fracturing under transient earthquake loading by random discrete element method

Abstract

Earthquake can cause significant rock fracturing in either the short or long terms. A comprehensive analysis of the fracturing mechanism is critical for assessing the risks of potential slope failures, landslides and rock avalanches in seismic prone areas. This study employed 2D discrete element method (DEM) to investigate the fracturing of an intact rock slope of 600 m in base length and 300 m in height, with explicit considerations of material heterogeneity by random field theory. A total of 5400 DEM simulations were performed, and the characteristics of slope fracturing were statistically analysed. The dynamic loading by earthquake has triggered significant amplifications of ground motion and slope damage at the slope crest, resulting in densely spaced and interconnect fractures. These fractures split the slope into a collection of rock fragments with varied shapes, and the fragment size followed the Weibull's cumulative distribution. More than 70% of generated fragments were finer than 0.1 times the initial slope size, while only few large fragments existed at the slope base. The fragment size distribution pattern could quantitatively agree with field observations. The distributions of final slope damage index and cumulated fragmentation energy all followed the normal distribution pattern. The overall bulk seismic energy input into the slope was dissipated mainly at discontinuities and decreased with the increase of slope inclination. • Differential ground displacements exist widely within the slope, which is critical for earthquake induced fractures. • The sizes of the generated rock fragments follow well the Weibull's cumulative distribution. • Statistically, the slope damage index and fragmentation energy all follow the normal distribution pattern. • The slope damage intensity decreases with the increase of slope inclination angle.