TYPES,CHARACTERISTICS AND SPATIAL DISTRIBUTION LAW OF LANDSLIDES AND COLLAPSES ALONG SICHUAN-TIBET RAILWAY

Frequent mountain hazards are one of the most critical factors for the successful construction of Sichuan-Tibet railway. Based on remote sensing interpretation, field investigation and mathematical statistics, we analyzed and summarized the types, characteristics and spatial distribution law of the landslides and collapses along Sichuan-Tibet railway. We identified 747 hazards along the railway, including 310 collapses, 413 landslides and 24 sand-sliding slopes. The average distribution line density of the hazards is 0.40 point/km, Baiyu to Jiangda section has the biggest line density(1.29 place/km). 258 mountain hazards have a potential threat and influence on the proposed railway engineering, including 156 landslides, 91 collapses and 11 sand-sliding slopes. In addition, we analyzed the relationship between the hazards and their impact factors. We found that the distribution of the hazards is comprehensively controlled and influenced by lithology, structure, geomorphology, river system and other factors, and has the characteristics of uneven and clustered distribution. On this basis, the development degree of landslides and collapses along Sichuan-Tibet railways was divided into 5 levels and 14 segments combining the development degree index of the hazards with the subsection standard. The Baiyu to Jiangda section, Bangda to Basu section are extremely strong development sections, Tianquan to Xindu section, Guxiang to Layue section and langxian to Jiachasection are strong development sections for the hazards. This study can provide an important scientific theory and decision-making support for line selection and safe operation of Sichuan-Tibet railway.