Assessment of Geohazards along Highways Based on the Weights of Evidence and GIS: A Case Study in Guangxi Province, China

Abstract

Geological disasters damage highways and disrupt traffic, which reduces the service level of roads. We collected 15,435 geohazards in Guangxi Province. The geohazards within 1km of the highway buffer were selected to study its spatial distribution characteristics and risk assessment methods. Geohazard intensity index and sensitivity index are proposed to establish the highway geohazards assessment model. Based on the weights of evidence (WOE) method, the influencing factors of the sensitivity index and the weight of each factor are obtained. By analyzing the spatial distribution characteristics of geohazards, collapses, landslides, ground collapse and unstable slopes are identified as major geohazards along the highway. Based on the Getis-Ord Gi* statistic methods, the hotspot map of four disasters was drawn, and the intensity index along the highway was calculated. The relationship between slope, aspect, topographic relief, annual average rainfall, land use, lithology type and geohazards was analyzed. The sensitivity index was calculated using the WOE method. The intensity index and the sensitivity index were superimposed to obtain the geohazard index, and the geohazard risk of the highway is divided into five levels. The model accuracy-test based on the receiver operating characteristic (ROC) curve shows that Area Under Curve (AUC) equals 0.71, indicating high reliability for the risk assessment.