Abstract:WenChuan Earthquake brought out large-scale and group-occurring secondary mountain hazards. They not only severely destroyed the highways and blocked the traffic

but also blocked the process of earthquake relief and reconstruction. After the remote sensing monitoring and field survey in XuanKou-Yanmen part of the DuJiangyan-WenChuan Highway

the article describes the type and the distribution of the secondary mountain hazards and analyzes the damage of the subgrades

pavements

bridges and tunnels along the DuJiangyan-WenChuan Highway. In addition

combining with the temporal characteristics of secondary mountain hazards

the article puts the countermeasure and suggestion of the relief and reconstruction of the traffic system. The research result shows that: (1)In the research region

strong earthquake causes a lot of secondary mountain hazards such as collapses

landslides

debris flows

dammed lakes. There are 3863 collapses with a total area of 68.9km2

74 debris flow gullies

18 landslides

5 dammed lakes

5 ground fissures which is longer than 1km.((2)Earthquake and secondary mountain hazards severely destroyed the highway and traffic. From XuanKou to YanMen in WenChuan

there are 299 blocks in DuJiangyan-WenChuan Highway. Also

there are barriers with a length of 23.814km. 80% of the highway

including 87 bridges and 10 tunnels

has been destroyed. (3)The distribution of the main kind of collapse

landslide

debris flow

dammed lake mainly depends on seismic intensity

geological structure

topography and geomorphology and rock characters.4) By using the technology of GIS and remote sensing

the disaster evaluation and dynamic monitoring can be effectively carried out

so it can provide the scientific basis and references to the relief and reconstruction.