Novel mangrove-guard baffles for rock avalanche protection : numerical analysis

Abstract

Rock avalanches pose significant threats to infrastructure due to their high kinetic energy. Baffle structure serves as an effective engineering solution for mitigating rock avalanche hazards. In this study, a new mangrove guard baffle (MGB) was proposed by combining traditional baffle (TB) designs with the prop root structure of mangroves. Using EDEM software, simulations were conducted to analyze the impact of baffle type and particle size on the movement velocity, deposition, impact force, and kinetic energy of rock avalanches. The results indicated that the process of rock avalanche impact on a baffle could be divided into four stages: initiation, acceleration, impact, and static deposition. The maximum average front velocity obtained by the rock avalanche in the acceleration phase was about 4.5 m/s, and the maximum average tail velocity was about 3 m/s. In addition, the MGB created a larger dead zone and reduced the deposition area. Compared to the STB, under the SMGB, the deposition areas of M1–M4 decreased by 17.9%, 12.7%, 17.1%, and 16%, respectively. MGB demonstrated superior impact force dissipation. When the number of baffle rows was three, the impact force dissipation rate of SMGB on M4 reached 99%. Compared to TBs, the momentum of the rock avalanche was reduced by 1%–3%. Considering the economic benefits and protection performance, the arrangement of two rows of baffles could be the best solution. These findings provided insights into the design of baffle structures against rock avalanches.