Seismically-Induced Rock-Slope Failure: Numerical Investigation using the Bonded Particle Model

Thesis (Ph.D.)--University of Washington, 2016-06

Seismically-induced rock-slope failures have caused the deaths of tens of thousands of people and economic losses in the billions over the last century. They are among the most common, dangerous, and still today, least understood of all seismic hazards. This research aims to further the understanding of seismically-induced rock-slope failure by studying the initiation and growth of fractures in rock-slopes during seismic loading. The Bonded Particle Model, which is commonly used in the static simulation of complex rock mechanics applications, is extended for use in fully-dynamic 2-dimensional simulation of rock-slopes. Using this model, the influence of ground motion characteristics and structural geology on the behavior and performance of rock-slopes during earthquakes is explored. The results show that dynamic stresses that develop within rock-slopes make the face of the slope particularly susceptible to damage. As damage accumulates in rock-slopes during dynamic loading, slopes can soften and become more sensitive to lower frequency input. Loading amplitude and frequency have a substantial impact on the seismic performance of rock-slopes, and this impact is highly dependent on the internal geologic structure of the rock-slope. The model results are consistent with observations of several historical earthquake-induced rock-slope failure events, and provide insight into the fundamental mechanisms behind seismically-induced rock-slope failures.