Slope Stability Assessment along Qalachwalan-Suraqalat Main Road, Sulaimani, NE-Iraq


Rock failures are extremely frequent along the cut slopes of the road in the mountainous terrains of the Iraqi Kurdistan region. Qalachwalan – Suraqalat road which is to the north of Sulaimani city is one of the major transportation ways between Sulaimani city and many towns and villages of Sharbazher district. Sometimes, this road (especially in winter and spring seasons) shows many rock failures that causing hazards for locals and traffics. Therefore, the stability assessment of road-cut slopes along such road is very necessary.For the present study ten (10) slope stations have been chosen from the road stretch of 10 Kilometers from Qalachwalan to Suraqalat, and this for stability assessment of the rock slopes with different techniques. The slope stations were chosen on the basis of difference in discontinuities pattern, variation in slope morphology and difference in the type of failure and the data were analyzed for their potential degree of stability by kinematic analysis, using DIPS v6.008 software and slope mass rating system [discrete-SMR and continuous-SMR (CSMR)], using SMR Tool - v205 software.Kinematic analysis revealed that planar sliding may occur in slopes of station 5, 7 & 9, wedge sliding in slopes of station 2, 3, 4, 5, 6, 8 & 10, flexural toppling in slopes of station 1, 2, 3, 4, 6, 7, 8 & 10 and direct toppling in slopes of station 1, 2, 4, 5 & 7.In the worst condition, the discrete-SMR and CSMR values for slopes in all stations range from 22-46 and 18-46 respectively, so It is observed that the values at slope station 1, 2 & 6 lie in partially-stable zone, with failure probability of 0.4, the values at slope station 4, 5, 7, 8, 9 & 10 lie in unstable zone, with failure probability of 0.6 and the value at slope station 3 lies in completely-unstable zone, with failure probability of 0.9