Assessing the impact of rockfall on the retaining structures of a mountain road: a case study in Taiwan

A destructive rockfall event occurred in northern Taiwan, wherein the falling blocks severely damaged the retaining structures of a mountain road. To elucidate the trajectory of rockfalls, a series of investigations was conducted to produce high-precision topographical models. In addition, the discontinuity distribution of the source area, geometries of the fallen blocks, and damage to the retaining structures were measured. These data were used to perform a full-scale three-dimensional numerical simulation of the rockfall event and its influence area. The runout paths and velocity variations of the rockfall and structural damage were successfully simulated. Furthermore, potential areas affected by subsequent disasters were evaluated using scenario modeling. This study proposed a method for analyzing the impact of rockfall on the retaining structure, which provides more information than the runout path and kinetic energy of the block, as well as the failure mechanisms and condition of impacted structures.