The use of Cone-Fall Theory for Evaluation of Rock-Fall Hazard along the Chaloos-Road(Pol-e-Zanguleh - Marzan-Abad)

Karaj-Chaloos Road is always considered as the most hazardous road due to rockfalls and landslide events. The road, located in the Central Alborz Mountains, is a vital route connecting Tehran and the southern part of Alborz to the northern part and the resort areas along the Caspian Sea. The aim of this paper is to study and evaluate the potential of rockfalls and landslides along the middle part of the route. The study area has a very complicated geological and geomorphological condition and many deep cuts were made along the road to provide a safe passage through the mountains. Since most of the slope instabilities along the road are of rockfall type, cone-fall theory proposed by Evans and Hungr (1993) was used to analyze and predict the rockfalls along the route.The results show that the potential of rockfall is directly related to morphology and higher for steeper slopes. Rock type and the geological structures of the slopes also influence the rockfall potential in the study area.