Quantitative Hazard Assessment Of Highway Slope Geological Hazards In The North Of Shaanxi Province

Shaanxi Province is the transportation hub of the city in Northwest China, the high-speed and trunk routes in the province connect to the vast western regions. The North of Shaanxi Province is located in the Loess Plateau area, the weather changes largely by season, its terrain is very complex, there are many highway slope of geological disasters and the losses are serious. So it’s necessary to study on the quantitative hazard assessment of highway slope geological hazards in the north of Shaanxi province.Based on the conclusion of previous scholar’s research production referring to the investigation of geological disasters and the “Hazard Information Database" of trunk roads in Shaanxi province. The evaluation index system, composed of 17 assessment indexes, has been built in terms of the database statistics for potential threats of highway slopes and the analysis of hazard characteristics and rules; furthermore, the system is divided into five influencing factors, including geological conditions, geometric features, environmental factors, failure characteristics, and the others.Taking northern Shaanxi as an example. First of all, qualitative evaluation indexes are re-encoded. The K-mean cluster analysis was utilized to classify the hazard slopes into six groups.Cluster group two and three slopes are selected to do factors analysis. 90 percent of slopes data is extracted from each of those two types of slope; six irrelevant common factors are selected from index system through trial and error. Six different common factors’ calculation model are obtained from two categories by component score coefficient matrix, and the corresponding contribution rate of accumulated variance is assigned to the weightings of each common factor.The evaluation models of Cluster group two and three slops are build. The risk values of 90 percent slopes involved in the modeling are obtained from calculation, then these values are normalized. According to the characteristics of cumulative frequency graphic on risk values and verification of filed survey, two types are grouped into five risk rating criteria, and the determination of detail rating range is as follows: extreme high degree of risk(1~0.9), high degree of risk(0.7~0.9), medium degree of risk(0.5~0.7), low degree of risk(0.3~0.5) and extremely low degree of risk(0.1~0.3). Eventually, risk values and ratings are obtained by risk assessment on those 10 percent slopes which are not involved in evaluation from cluster group two and cluster group three. With reference to the practical risk condition of the highway slopes, the paper verifies correctness of the evaluation model.This quantitative modle will guid the hazard assessment slope geological hazards along the trunk routes in Shaanxi province. it is a beneficial attempt, and furthermore, lay a foundation for the risk assessment on slopes.