Blocking-baffle mechanism of vegetation to rock avalanche on the forested slope of the east Sichuan-Tibet Mountains

The forest could be a protective structure to reduce rock avalanches in the Sichuan-Tibet Mountains. When rocks propagate down a forested slope and hit trees, they are blocked, modified in trajectory, slowed down, and deposited, which weakens their destructive effect directly on the downstream. To better understand the protective effect of forests against rock avalanches, a novel material point method (MPM) introducing two contact models describes the rock avalanches’ movement on slope and interaction with trees, respectively. Carry out simulations on an idealized scenario of rock avalanches to conduct extensive parametric studies, which give the shape, volume, thickness, and runup height of rock accumulations, showing how shapes, species, and layout of trees have vital effects on blocking the rock avalanches. Finally, an optimal green protective structure for a vegetation-free slope in a 3D valley is given, and the blocking-baffle mechanism of vegetation to rock avalanches on mountains is illustrated clearly through numerical calculations.