Assessment of landslide Possibility Index and Rockfall Hazard Rating System for slopes in Qaywan Mountain, Sulaimani Governorate, Northeastern Iraq

The current study includes assessing road risks using a system Landslide Possibility Index (LPI) and Rockfall Hazard Rating System (RHRS) analysis along the Qaywan Mountain (anticline) main road 20 km north of SulaimaniGovernorate. Slope stability assessments consisted of seventeen stations along the main road in the study area. Along the outcropped rock units represented by formations, Balambo, Sarmord, Kometan, and Shiranish, a thorough discontinuity assessment and a regional survey of slopes were carried out. Along the cut slopes, rockfall is the primary type of failure, in addition to possibility types of landslide failures in the studied area is plane sliding, wedge sliding, and toppling because cutting rocks to build roads, slope direction and slope angle, dip and dip direction of discontinuities. The (LPI) indicates all the slopes studied in 17 sites in the surveyed area along the road were classified as high hazard. According to the analysis results of the RHRS, the score ranges between 177 and 375. Site no. 5 (375) has the highest rating value indicating a moderate hazard that requires remedial measures to be taken with a moderate level of urgency and site no.8 has the lowest value noted (177). It is the only site that falls under this rating, which is classified as a low hazard and slopes do not require detailed studies.