عنوان مقاله [English]
Steep slopes developed on the loose ground either natural or artificial are prone to landslide phenomenon. During construction activities for the development of new Qaen-Afin road in South Khorasan and adjacent to Ravoshk village a sudden landslide occurred in a shale slope and newly-built stone bridge for the road destructed. In this paper, using geologic conditions, satellite images, the field evidence of landslide and SLIDE6 and Phase2 programs, the type, and cause of the landslide will be examined. The survey conducted with the help of satellite images and field visits showed that the landslide occurred is a circular landslide with dimensions of approximately 50 × 80 m. It had happened a few months ago, but unfortunately, no attention paid to it and continued construction activities in the rainy season stimulated the sliding mass and led to extreme conditions. The geometrical condition of the slope just before the slope failure determined with the help of GPS, surveying meter, and satellite images. Using this information, the two-dimensional model of the natural slope, before any construction activity, created in SLIDE6. Slope stability analysis was performed using simplified Bishop limit equilibrium method, and failure of the slope predicted successfully. A finite element analysis of the slope in Phase2 software arrived at similar results. This paper has shown that lack of attention to first slope movements and continuing construction work was the primary cause of financial losses incurred.