Hazard Assessment of Highways Affected by Debris Flows: Fid-Bau Portal

Hazard Assessment of Highways Affected by Debris Flows

Zou, Qiang

Roads often run across various drainage basins in mountain areas which include complex geographic and geomorphic conditions. Highways in these areas have been frequently interrupted by debris flows. Without emergency management planning, such debris flows can lead to extensive life and property loss. Through analyzing the hazard effect modes and damage process along highways, we developed three key indexes, scale of debris flows, deposits on highways and river blockage, to describe the highway disasters quantitatively. According to actual investigation, we proposed new methods to determine the value of hazard indexes. Subsequently, we developed the assessment and mapping methods for highways safety by using hazard degree of debris flow. The hazard is graded into 4 grades as extreme low, low hazard, medium and high hazard level. Through applying this method, a case study was carried out on national highway G318 in Xiqu River basin. After analyzing debris flow hazard for the whole highway, the assessment results are consistent with the field surveyed data which indicate actual disaster situation. This hazard method can objectively evaluate the debris-flow hazard along highways, and is useful for highway reconstruction in mountainous areas suffering from active debris flows.