Assessment of the stability of the cut rock slopes between Bağlarbaşi-Tekke (Gümüşhane)

In this study, RMR and GSI rock mass classifications are made on seven different-cut slopes which outcropped Late Carboniferous Aged Gümüşhane Granitoid between Bağlarbaşı-Tekke (Gümüşhane), as well as the examination of the stability of the highway slopes with the numerical (finite element method) and kinematic analysis methods. According to the RMR classification, the Basic Rock Mass Rating was evaluated each of rock slopes, and was determined to be in the "Fair Rock" feature. In addition, according to the GSI classification, each rock slope has "Blocky/Disturbed" characteristic. For each slope examined, rock mass deformation modulus were calculated basing on RMR and GSI empirical classifications and empirical equations, and as the result, the modulus values varying between 3.04-5.63 GPa. The evaluation of the orientation measurements, which were taken from discontinuity of the cut rock slopes shows that there are three sets of discontinuity on Slope 2 and Slope 5, and four sets of discontinuity on the other slopes. Stability of each rock slope was calculated by numerical and kinematic analysis methods. According to these evaluations, the number slopes 3, 4, 5, 6 and 7 which are determined to be unstable. Without changing the dip direction, critical slope angles of the mentioned slopes was evaluated basing on numerical analysis methods and safety coefficients was set above 1,5. According to this, if the slope angles are respectively reduced to; 48°, 40°, 55°, 44° and 65°, the instability issue will be eliminated. Thus, both instability issues depending upon the discontinuity and the circular failure issue will be prevented. Keywords: Gümüşhane Granitoid, GSI, Kinematic Analysis, Numerical Analysis, RMR, Slope Stability