Risk Assessment of Debris Flow in Strong Earthquake Area

Abstract

The construction and operation of the Jiuzhaigou County bidding section of the Jiumian Expressway is affected by debris flow disasters. It is important to scientifically and reasonably evaluate the debris flow risk in the engineering area. Therefore, according to the data of topography, meteorology, hydrology and regional geological structure of the project area, 12 influencing factors, such as regional geological disasters, loose material reserves along the gully and maximum punching amount at one time, are selected as the evaluation indexes of debris flow risk assessment. Based on the catastrophe progression method, a mutation model of debris flow risk assessment suitable for the project area was established. The debris flow risk assessment mutation model was used to evaluate the debris flow risk of 8 trenches in the project area, and the applicability of the model is verified by comparing the actual occurrence history of debris flow in the trench with the evaluation results. The analysis results show that the risk of debris flow in four gullies of Gangou and Xiaganzuo in the bid section project area of Jiuzhaigou County of Jiumian Expressway is extremely dangerous, and the debris flow risk of Shangganzuo gully is severe. These five debris flow gullies are the key objects of debris flow prevention and control during the construction and operation of Jiuzhaigou County bidding section of the Jiumian Expressway.

Debris flow gully zoning and risk assessment based on numerical simulation

“…represents the probability of exceeding Grade I, II and III losses respectively [6] . As shown in Figure 2, the probability of building exceeding loss increases with the increase of debris flow intensity, especially when I DF is 20~50m 3 /s 2 , the increase is most obvious, and buildings are more vulnerable to serious damage.…”