Stability evaluation of slopes formed by the shales in İzmir and its vicinity

Sliding, settling, swelling, water dispersion and disintegration are the main engineering problems observed in shales. In the present study, some examinations and studies were undertaken to determine stability and engineering behaviour of slopes. In addition, rock mass classification (GSI) was performed on shales which present laminated, fractured, weak rock characteristics and some engineering properties of rock mass (modulus of deformation, intact uniaxial comp. strength, cohesion and friction angle ) were determined. The stress levels which shale rock mass is exposed in the field conditions for 10m, 12m, 15m and 20 m slope heights were determined by utilizing RocData software and shear box tests were also performed by considering these stress levels. Stability analyses were conducted by using Slide V. 6.0 software. The variation of safety factor was examined by performing firstly, rotational failure, secondly planar failure analyses for various seismic coefficients (0,1 g, 0.12 g, 0.15 g, 0.18 g, and 0.20 g) and cohesion values (18 kN/m2, 25 kN/m2, 45 kN/m2, and 60 kN/m2). The effects of seismic coefficient and cohesion strength variations on the slope stability were investigated. As a result of this study, stability conditions for excavation slopes in shales were obtained.