Risk Zoning for Susceptibility to Highway Geohazards in the Sichuan-Chongqing-Hubei Region

Highway geohazards are prevalent in the Sichuan–Chongqing–Hubei region, conducting susceptibility risk zoning for these disasters provides crucial scientific support for implementing disaster prevention forecasting and risk assessment along highways. In the present study, data from 2014 to 2022 were utilised, encompassing highway geohazard-induced traffic disruptions, precipitation records, and basic geographic information, to investigate geohazard susceptibility. A total of 11 susceptibility indicators were selected, integrating geological, environmental, topographic and meteorological parameters. Susceptibility indices and triggering probabilities were employed to examine the key influencing factors of highway geohazards, followed by systematic classification of the indicators. To quantify the relative importance of each indicator, the entropy weight method and analytic hierarchy process were applied, facilitating the evaluation and spatial delineation of geohazard susceptibility risk levels.The results demonstrate that susceptibility index and triggering probabilities effectively reflect the characteristic factors influencing highway geohazards. Key triggering factors include: semi-luvisols as the dominant soil type, grassland as the land-use type, peak ground acceleration (PGA) exceeding 0.3g, fault distance within 3 km, river distance within 0.5 km, 24-hour cumulative precipitation exceeding 100 mm, effective precipitation exceeding 100 mm, and consecutive rainfall events lasting 3–5 days. The risk zoning map generated using the entropy weight method effectively reflects the spatial distribution patterns of highway geohazards. High and moderately high risk zones are primarily concentrated in high-altitude mountainous regions, notably in the central-western and southern areas of Sichuan Province, the eastern and south-western parts of Chongqing Municipality, and the western and eastern regions of Hubei Province—areas characterised by a high incidence of highway geohazard events.