Effects of the configuration of a baffle–avalanche wall system on rock avalanches in Tibet Zhangmu: discrete element analysis

Rock avalanches with a high mobility and kinetic energy pose a potential geological risk to surrounding buildings. Baffles and avalanche walls are effective ways to protect these buildings. However, the primary focus of previous studies has been on baffles or avalanche walls alone, and there have been very few studies investigating the effectiveness of a combination of baffles and avalanche walls as a countermeasure against rock avalanches. In addition, previous studies on lab-scale tests and numerical analyses often did not take the actual topography effects into consideration. In this study we adopted a numerical simulation approach based on an actual project in the town of Zhangmu, Tibet, with the aim to investigate the effect of different configurations of a combined baffle–avalanche wall system on impeding the kinetic energy of rock avalanches. A series of numerical analyses with discrete element methods (DEM) were conducted. First, the effect of three different pile groups on the reduction of the effect of the rock avalanche was studied using the numerical modeling study. Secondly, the influence of the size of the retaining wall on the maximum impact force of the rock avalanche was studied. Finally, a DEM modeling study on the energy dissipation capacity of the baffle–avalanche wall system was conducted. The results demonstrate that an arrangement of different baffle–avalanche wall systems will produce different results in terms of dissipating the energy of rock avalanches: when the wall is long enough to block all rock masses, enhancing baffle density will decrease the maximum impact force exerted on the avalanche wall; however, if the wall is just long enough to protect the target region, reducing baffle density will decrease the maximum impact force exerted on the avalanche wall. The results of this study are significant in terms of providing guidelines for the design of baffle–avalanche wall systems for protection against rock avalanches.