Performance of Vetiver-Reinforced Slopes: Full-Scale Deformation Monitoring and Coupled Hydro-Mechanical Numerical Simulation under Extreme Climate Conditions

Extreme climate conditions characterized by intensified rainfall and prolonged drought have increased slope susceptibility to hydro-mechanical deterioration and rainfall-induced instability. This study evaluated the serviceability performance of a full-scale vetiver-reinforced slope through one year of field deformation monitoring and coupled hydro-mechanical numerical simulation under seasonal and projected extreme climate conditions. The results showed that the vetiver-reinforced slope consistently exhibited lower horizontal deformation and more stable pore water pressure (PWP) responses than the bare slope. During the early rainy season, vetiver reduced horizontal displacement by approximately 44% through root reinforcement and hydraulic regulation. Conversely, its influence on vertical settlement was relatively limited, indicating that vetiver primarily enhances slope stability rather than mitigating consolidation-induced settlement. Seasonal deformation also differed, with settlement dominated by shrinkage during the dry season and horizontal displacement increasing during the rainy season due to rainfall-induced instability. Under the RCP 8.5 climate scenario, vetiver remained effective in limiting deformation, demonstrating its potential as a climate-resilient nature-based solution for sustainable slope stabilization.