Comparison Regarding the Effects of Different Baffle Systems as Impacted by Rock Avalanches

Abstract

Baffle array is generally embedded ahead of the protecting site for reducing rock avalanche’s flow energy. This study explored the arc-shape baffles in comparison with common baffles (cylindrical and square baffles) according to the application of science in practice. The comparing process of three categories of baffles was delved into experimentally, primarily highlighting the disaster reduction effectivity. The comparison of disaster reduction effective between these three categories of baffles is analyzed by three elements, which are deposition, VRR (velocity decrease rate), and U* (dimensionless velocity). Based on the rock avalanche final deposition, the optimal configuration for arc shape, square, and cylindrical baffles satisfy Sr = 4.5 and Sc = 3.5, Sr = 4.5 and Sc = 4.5, and Sr = 4.5 and Sc = 2.5, separately. As suggested from the results, the arc-shape baffle is the optimal case among those three categories of baffle. Shape alteration (cylindrical to arc-shape) can elevate the fragment block degree; the succeeding avalanches can occur around the avalanche deposits, causing kinetic energy to dissipate significantly. Besides, based on the contrast of VRR, U*, and deposition, arc-shape baffle mechanism was reported significantly superior to block. The energy dissipation system of the arc-shape baffle is primarily explained as: (1) the friction of rock fragment will be generated in the movement around the arc surface, thereby causing additional loss of kinetic; (2) a natural cushion is formed when rock fragment accumulated between the arc-shape baffle, being critical to energy dissipation for subsequent rock avalanches.