The response characteristics and stability evaluation of vegetated slope under strong wind

As one of the major geological disasters in southeastern China, typhoon-induced vegetation slope instability causes significant loss of life and property each year. Despite the criticality of this issue, the response mechanism of vegetated slopes to wind loading in terms of soil deformation and stability still remains unclear. This research conducted field investigations on 330 historical landslides in Yongjia County, Zhejiang Province, analyzing their spatiotemporal distribution and developmental characteristics to establish a conceptual model. The influence of wind and vegetation conditions on slope dynamic parameters and soil strength parameters were subsequently determined through numerical simulations using FLAC3D software, model tests, and direct shear tests. The results show that: (1) The influence of wind on the dynamic response of vegetated slopes is significantly affected by wind speed. At wind forces ≤ 12 (hurricane: 32.7–36.9 m/s), vegetation plays a positive role in enhancing slope stability. At wind forces ≥ 13 (typhoon: 37.0–41.4 m/s), vegetation exerts a negative influence under the combined action of strong wind loads. (2) Based on the experimentally determined evolution of soil strength parameters, a formula c (v, w) was fitted to express the variation of cohesion with wind speed (v) and moisture content (w). (3) The optimized evaluation model demonstrates increased sensitivity compared to the traditional model, resulting in a 17.88% increase in sliding force and a 10.62–11.64% increase in anti-sliding force. This research accounts for both the direct and indirect effects of wind loading on vegetated slopes. The findings are expected to enhance the stability assessment of vegetated slopes under strong winds and facilitate the development of more accurate machine learning and statistical models in the future.