Evaluation of rockfall hazards along part of Karaj-Chaloos road,Iran

摘要

Karaj-Chaloos Road is a vital route that connects Tehran and the southern part of Alborz to thenorthern part and the resort areas along the Caspian Sea. The road is located in the Central Alborz Mountainswhere the occurrence of rockfall hazards is always considered to be very high. The event of May 28th 2004earthquake triggered a large number ofrockfalls along the road which caused human casualties and huge damagesto the infrastructures along the road. The aim of this paper is to evaluate the potential of rockfalls along partof the route between Pol-e-zangoleh and Marzan-abad. The study area has a very complicated geological ageomorphological conditions. Since most of the slope instabilities along the road are ofrockfalls type,rockfallstheory proposed by Evans and Hungr (1993) was used together with CONEFALL program (introduced byJaboyedoff,2003) to analyze and to predict the potential of rockfalls along the road. Many factors such rocktype,slope morphology,drainage pattern and the seismic activity were considered in this research as mainaffecting factors. Based on GIS program a rockfall hazard zonation map was prepared. It was found that about45% of the rout has a high potential of rockfall activity and slope morphology is the most affecting factor for thedevelopment of rockfalls. The influences of other factors such as rock type,fault alignment were found to be less.