ABSTRACT
This paper describes a part of massive landslides and slope failures, which regularly occur in the area of Chaharmahal and Bakhtiari Province, South-West of Iran. The landslides and slope failures under consideration are located along a part of very important and strategic road. The road with a total length of 350 kilometer connects central parts of Iran to the west parts. In recent years, landslides in the forms of slumping, mud flow, rock falls, and debris flows have been observed along the road. In the present paper attention is paid to describe the details of landslides and slope failures associated with softening of clayey marl soil after saturation due to rainfall. These landslides and slope failures have recently occurred at 32 locations along 50 kilometer of the road between Bahesht-Abad Village and Samsami Village. The nature of failures are illustrated using available recorded documents. The effects of different factors such as geological and geotechnical properties of soils, slope geometry, road construction, etc. on instability of slopes after soil softening due to increase in degree of saturation of the soil will be described. The results of the analysis of slope failures in the area will be explained in the companion paper by the authors.
