Dynamic analysis of multi-block rockfalls using improved 3-D discontinuous deformation analysis: Effect of coefficient of restitution

Abstract

Rockfalls are a frequent hazard in mountainous regions, posing significant risks to both people and infrastructure due to their high velocity, mass, and energy. However, understanding the dynamics of multi-block systems remains challenging because of their inherent complexity, complicating accurate predictions. This study focuses on the critical role of the coefficient of restitution (COR) in governing the dynamic behavior of multi-block rockfalls. To address this, an improved three-dimensional discontinuous deformation analysis (3-D DDA) method is developed and applied to simulate energy dissipation during collisions in multi-block rockfalls. The improved 3-D DDA is validated through comparisons with theoretical and experimental rockfall models. Using this method, simulations of multi-block rockfalls with varying COR values are conducted to examine their influence on rockfall dynamics and deposition patterns. The analysis also incorporates friction angle to explore its interaction with the block-ground COR. Results reveal that in high-COR path materials, such as rock slopes, the sliding friction coefficient becomes a more influential factor in determining rockfall runout distances. Additionally, the integration of the 3-D DDA method with 3-D scanning technology enables simulations using real-world block geometries, facilitating the investigation of block sphericity effects. The proposed method offers a robust framework for analyzing multi-block rockfall mechanisms, improving both prediction accuracy and post-failure assessments.