Risk Evaluation Indicator And Methodology For Geological Hazards Of Highway Roadbed

With the rapid development of the economy in China, highway construction as national basic facilities develops quickly. Highway traffic becomes more and more important to economic development and promotion. Because highway is a strip structure, it often needs passing through different terrain units, and some cacoethes geological environment sometimes. Collapse, landslide, debris flow and subgrade settlement of geological hazards and so on occur frequently, especially in the west mountainous area in China. Because of the complex terrain and complex geology condition, a plenty of geological hazards occur every year. Geological hazards not so serious may cause traffic jam or interruption, while serious disaster may cause vehicle destruction and death. Because the risk evaluation is the basis for the disaster management, study on the evaluation index and evaluation methods of the geological hazards of subgrade is very important for making reasonable decision of the disaster prevention and reduction for the managers.The thesis bases on the relevant contents of West Region Communication Construction Technology Project of the Ministry of Communications-The Extension and Application Demonstration of Hazards Prevention for Roadbed Damage.Frist, we widely collect previous researches of geological hazards for subgrade at home and abroad. By multiple field investigation of highway geological hazards and collecting the diaster date on the support project-G316 in Shaanxi province, the characteristics and forming mechanism of collapse, landslide, debris flow and roadbed subsidence of geological hazards are analysed and summarized.Second, the factors influencing of collape, landslide, and debris flow and so on are analysed systematically. From environmental conditions and evoking factors of hazards, the major and controlling influence factors are summarized as evaluation index. And classification standards of the factors are established according to the actual condition. According to the theory and methods of the geological hazards of subgrade, comprehensive index method and AHP are selected for the geological hazards of subgrade, based on the characteristics of highway engineering.Then, the theory and comprehensive evaluation method of the geological hazards of subgrade is studied. The supporting project-G316 from Ankang to Hanzhong in Shaanxi province is divided into 41 evaluation elements. Using the evaluate results of monomeric hazards, relevant comprehensive evaluate model is established. Using risk division method comprehensive evaluation of geological hazards is performed.Finally, relying on the site investigation and data analysis, evaluation methods and evaluation model is validated. The monomer assessment of geological disasters in G316 and comprehensive evaluation of the risk of the section are done based on the results of the evaluation and on-site survey data. Comparing with the analysis of historical disaster data, it shows that the results of the evaluation and historical disaster data are basically consistent.